Encoder, decoder and corresponding methods of most probable mode list construction for blocks with multi-hypothesis prediction

ABSTRACT

The present disclosure relates to the field of picture processing. Especially, the disclosure deals with improving the prediction of a block of a picture when decoding or encoding. A method of coding a block of a picture, comprising: obtaining an indication parameter for a current coding block. The indication parameter represents whether a multi-hypothesis prediction is applied to the current coding block. When the indication parameter represents that the multi-hypothesis prediction is applied to the current coding block, coding the current coding block according to a planar mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of international applicationPCT/CN2019/122153, filed on Nov. 29, 2019, which claims the benefit ofU.S. Provisional Application No. 62/773,149, filed on Nov. 29, 2018 andU.S. Provisional Application No. 62/783,149, filed on Dec. 20, 2018, Allof the aforementioned patent applications are hereby incorporated byreference in their entireties.

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to the field ofpicture processing and more particularly to construct a most probablemode list.

BACKGROUND

Video coding (video encoding and decoding) is used in a wide range ofdigital video applications, for example broadcast digital TV, videotransmission over internet and mobile networks, real-time conversationalapplications such as video chat, video conferencing, DVD and Blu-raydiscs, video content acquisition and editing systems, and camcorders ofsecurity applications.

The amount of video data needed to depict even a relatively short videocan be substantial, which may result in difficulties when the data is tobe streamed or otherwise communicated across a communications networkwith limited bandwidth capacity. Thus, video data is generallycompressed before being communicated across modern daytelecommunications networks. The size of a video could also be an issuewhen the video is stored on a storage device because memory resourcesmay be limited. Video compression devices often use software and/orhardware at the source to code the video data prior to transmission orstorage, thereby decreasing the quantity of data needed to representdigital video images. The compressed data is then received at thedestination by a video decompression device that decodes the video data.With limited network resources and ever increasing demands of highervideo quality, improved compression and decompression techniques thatimprove compression ratio with little to no sacrifice in picture qualityare desirable.

SUMMARY

Some embodiments of the disclosure provide an improved method andapparatus allowing to reduce the complexity of decoding and, thus,increase the video decoding efficiency.

The foregoing and other benefits are achieved by the subject matter ofthe independent claims. Further implementation forms are apparent fromthe dependent claims, the description and the figures.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising: obtaining an indication parameter for a currentcoding block according to a bitstream, the indication parameterrepresents whether a multi-hypothesis prediction is applied to thecurrent coding block or not;

-   -   obtaining an index parameter for the current coding block        according to the bitstream;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block, obtaining an intra prediction mode for the current coding        block according to the index parameter and a predefined list,        wherein the predefined list comprises the following intra        prediction modes orderly: planar mode, DC mode, Vertical mode,        Horizontal mode; decoding the current coding block according to        the intra prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising obtaining an indication parameter for a currentcoding block according to a bitstream, the indication parameterrepresents whether a multi-hypothesis prediction is applied to thecurrent coding block or not;

-   -   obtaining an index parameter for the current coding block        according to the bitstream;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block, obtaining an intra prediction mode for the current coding        block according to the index parameter and a predefined list,        wherein the predefined list comprises the following intra        prediction modes orderly: planar mode, DC mode, Vertical mode;        decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising obtaining an indication parameter for a currentcoding block according to a bitstream, the indication parameterrepresents whether a multi-hypothesis prediction is applied to thecurrent coding block or not;

-   -   obtaining an index parameter for the current coding block        according to the bitstream;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block,    -   obtaining an intra prediction mode for the current coding block        according to the index parameter and a predefined list, wherein        the predefined list comprises the following intra prediction        modes orderly: planar mode, DC mode;    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block,    -   decoding the current coding block according to a Planar mode.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   obtaining an index parameter for the current coding block        according to the bitstream; when, according to a value of        indication parameter, the multi-hypothesis prediction is applied        to the current coding block,    -   obtaining an intra prediction mode for the current coding block        according to the index parameter and a predefined list, wherein        the predefined list comprises the following intra prediction        modes orderly: DC mode, planar mode, Vertical mode, Horizontal        mode;    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   obtaining an index parameter for the current coding block        according to the bitstream; when, according to a value of        indication parameter, the multi-hypothesis prediction is applied        to the current coding block,    -   obtaining an intra prediction mode for the current coding block        according to the index parameter and a predefined list, wherein        the predefined list comprises the following intra prediction        modes orderly: DC mode, planar mode, Vertical mode;    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   obtaining an index parameter for the current coding block        according to the bitstream; when, according to a value of        indication parameter, the multi-hypothesis prediction is applied        to the current coding block,    -   obtaining an intra prediction mode for the current coding block        according to the index parameter and a predefined list, wherein        the predefined list comprises the following intra prediction        modes orderly: DC mode, planar mode;    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block,    -   decoding the current coding block according to a DC mode.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode (MPM) list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        horizontal mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a first predefined range (in an example, the        range could be from 35 to 66, which include 35 and 66), adding a        vertical mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        horizontal mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in the first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding        another horizontal mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        horizontal mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in the first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        Planar mode, a DC mode and a vertical into the MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        horizontal mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in a second predefined range (in an example, the        range could be from 35 to 66, which include 35 and 66), adding a        vertical mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a second predefined range (in an example, the        range could be from 35 to 66, which include 35 and 66), adding a        vertical mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in the second predefined range (in an example,        the range could be from 35 to 66, which include 35 and 66),        adding another vertical mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a second predefined range (in an example, the        range could be from 35 to 66, which include 35 and 66), adding a        vertical mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in the second predefined range (in an example,        the range could be from 35 to 66, which include 35 and 66),        adding a Planar mode, a DC mode and a horizontal mode into the        MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        left block is in a second predefined range (in an example, the        range could be from 35 to 66, which include 35 and 66), adding a        vertical mode into a MPM list;    -   when the above block of the current coding block is available,        and a value corresponding to an intra prediction mode of the        above block is in a first predefined range (in an example, the        range could be from 2 to 34, which include 2 and 34), adding a        horizontal mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is not        available, and the above block of the current coding block is        not available,    -   adding a Planar mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is not        available, the above block of the current coding block is        available and an intra prediction mode of the above block is        Planar mode, adding a Planar mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is not        available, the above block of the current coding block is        available and an intra prediction mode of the above block is DC        mode, adding a DC mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is not        available, the above block of the current coding block is        available and a value corresponding to an intra prediction mode        of the above block is in a second predefined range (in an        example, the range could be from 35 to 66, which include 35 and        66),    -   adding a vertical mode, a DC mode, a Planar mode into a MPM        list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is not        available, the above block of the current coding block is        available and a value corresponding to an intra prediction mode        of the above block is in a first predefined range (in an        example, the range could be from 2 to 34, which include 2 and        34),    -   adding a horizontal mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is Planar mode and the        above block of the current coding block is not available, adding        a Planar mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is Planar mode, the        above block of the current coding block is available and an        intra prediction mode of the above block is Planar mode, adding        a Planar mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is Planar mode, the        above block of the current coding block is available and an        intra prediction mode of the above block is DC mode,    -   adding a Planar mode, a DC mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is Planar mode, the        above block of the current coding block is available and a value        corresponding to an intra prediction mode of the above block is        in a second predefined range (in an example, the range could be        from 35 to 66, which include 35 and 66), adding a Planar mode, a        vertical mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is Planar mode, the        above block of the current coding block is available and a value        corresponding to an intra prediction mode of the above block is        in a first predefined range (in an example, the range could be        from 2 to 34, which include 2 and 34),    -   adding a Planar mode, a horizontal mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is DC mode and the above        block of the current coding block is not available, adding a DC        mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is DC mode, the above        block of the current coding block is available and an intra        prediction mode of the above block is Planar mode,    -   adding a DC mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is DC mode, the above        block of the current coding block is available and an intra        prediction mode of the above block is DC mode,    -   adding a DC mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is DC mode, the above        block of the current coding block is available and a value        corresponding to an intra prediction mode of the above block is        in a second predefined range (in an example, the range could be        from 35 to 66, which include 35 and 66), adding a DC mode, a        vertical mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, an        intra prediction mode of the left block is DC mode, the above        block of the current coding block is available and a value        corresponding to an intra prediction mode of the above block is        in a first predefined range (in an example, the range could be        from 2 to 34, which include 2 and 34), adding a DC mode, a        horizontal mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a second predefined range (in an example, the range        could be from 35 to 66, which include 35 and 66), and the above        block of the current coding block is not available, adding an        vertical mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a second predefined range (in an example, the range        could be from 35 to 66, which include 35 and 66), the above        block of the current coding block is available and an intra        prediction mode of the above block is Planar mode, adding an        vertical mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a second predefined range (in an example, the range        could be from 35 to 66, which include 35 and 66), the above        block of the current coding block is available and an intra        prediction mode of the above block is DC mode, adding an        vertical mode, a DC mode into the MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a first predefined range (in an example, the range        could be from 2 to 34, which include 2 and 34), and the above        block of the current coding block is not available,    -   adding a horizontal mode, a Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a first predefined range (in an example, the range        could be from 2 to 34, which include 2 and 34), the above block        of the current coding block is available and an intra prediction        mode the above block is Planar mode, adding a horizontal mode, a        Planar mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   determining whether a left block (for example, block L in FIG. 6        ) of a current coding block is available or not (for example, if        there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available);    -   determining whether an above block (for example, block A in FIG.        6 ) of a current coding block is available or not (for example,        if there is no intra prediction mode of the above block, the        above block is not available, if there is an intra prediction        mode of the above block, the above block is available);    -   when the left block of the current coding block is available, a        value corresponding to an intra prediction mode of the left        block is in a first predefined range (in an example, the range        could be from 2 to 34, which include 2 and 34), the above block        of the current coding block is available and an intra prediction        mode the above block is DC mode, adding a horizontal mode, a DC        mode into a MPM list.

According to an embodiment, the disclosure relates to a method ofprocessing a block according to most probable mode, MPM, list, themethod comprising:

-   -   constructing a first MPM list for a current block according to        intra modes of neighboring blocks of the current block (in one        example, the MPM list of the current block comprises six intra        modes. In an example, one MPM list comprises one or more intra        modes means that the MPM list comprises one or more values        corresponding to one or more intra modes, one value        corresponding to one intra mode);    -   constructing a second MPM list of the current block according to        one or more intra modes of the first MPM list of the current        block;    -   obtaining an indication parameter for the current block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        block or not;    -   using, according to a value of indication parameter, the first        MPM list or the second MPM list to process the current block        (for example, the MPM list could be used in the intra prediction        of the current block).

In an embodiment, the method further comprises: the constructing asecond MPM list of the current block according to one or more intramodes of the first MPM list of the current block comprises:

-   -   when the second MPM list of the current block comprises one        intra mode, constructing the second MPM list of the current        block according to the first intra mode in the first MPM list of        the current block.

In an embodiment, the method further comprises the constructing a secondMPM list of the current block according to one or more intra modes ofthe first MPM list of the current block comprises:

-   -   when the second MPM list of the current block comprises two        intra modes, constructing the second MPM list of the current        block according to the first intra mode and the second intra        mode in the first MPM list of the current block.

In a possible implementation form of the method according to anypreceding implementation of the first aspect or the thirty-seventhaspect as such, the method further comprises the constructing a secondMPM list of the current block according to one or more intra modes ofthe first MPM list of the current block comprises:

-   -   when the second MPM list of the current block comprises three        intra modes, constructing the second MPM list of the current        block according to the first intra mode, the second intra mode        and the third intra mode in the first MPM list of the current        block.

In an embodiment, the method further comprises the constructing a secondMPM list of the current block according to one or more intra modes ofthe first MPM list of the current block comprises:

-   -   when the second MPM list of the current block comprises four        intra modes, constructing the second MPM list of the current        block according to the first intra mode, the second intra mode,        the third intra mode and the fourth intra mode in the first MPM        list of the current block.

In an embodiment, the method further comprises when the first intra modein the first MPM list of the current block is Planar mode, a Planar modeis added into the second MPM list (in an example, Planar mode is thefirst intra mode in the MPM list of the current block).

In an embodiment, the method further comprises when the first intra modein the first MPM list of the current block is DC mode, a DC mode isadded into the second MPM list (in an example, DC mode is the firstintra mode in the second MPM list of the current block).

In an embodiment, the method further comprises when a valuecorresponding to the first intra prediction mode in the first MPM listof the current block is in a first predefined range (in an example, therange could be from 2 to 34, which include 2 and 34), a horizontal modeis added into the second MPM list of the current block (in an example,horizontal mode is the first intra mode in the second MPM list of thecurrent block).

In an embodiment, the method further comprises a value corresponding tothe first intra prediction mode in the first MPM list of the currentblock is in a second predefined range (in an example, the range could befrom 35 to 66, which include 35 and 66), vertical mode is added into thesecond MPM list of the current block (in an example, vertical mode isthe first intra mode in the second MPM list of the current block).

According to an embodiment, the disclosure relates to a method ofconstructing a most probable mode, MPM, list for intra prediction, themethod comprising:

-   -   obtaining an indication parameter for a current block according        to a bitstream, the indication parameter represents whether a        multi-hypothesis prediction is applied to the current coding        block or not;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block,    -   determining whether a left block (for example, block L in FIG. 6        ) of the current coding block is available or not (for example,        if there is no intra prediction mode of the left block, the left        block is not available, if there is an intra prediction mode of        the left block, the left block is available),    -   when the left block of the current coding block is not        available, adding a Planar mode into a MPM list of the current        coding block (in an example, before this adding operation, the        MPM list of the current coding block may be an empty list).

In an embodiment, the method further comprises:

-   -   when the left block of the current coding block is available and        an intra mode of the left block is Planar mode, adding a Planar        mode into a MPM list of the current coding block (in an example,        before this adding operation, the MPM list of the current coding        block may be an empty list).

In an embodiment, the method further comprises:

-   -   when the left block of the current coding block is available and        an intra mode of the left block is DC mode, adding a DC mode        into a MPM list of the current coding block (in an example,        before this adding operation, the MPM list of the current coding        block may be an empty list).

In an embodiment, the method further comprises:

-   -   when the left block of the current coding block is available and        a value corresponding to an intra mode of the left block is in a        first predefined range (in an example, the range could be from 2        to 34, which include 2 and 34), adding a horizontal mode into a        MPM list of the current coding block (in an example, before this        adding operation, the MPM list of the current coding block may        be an empty list).

In an embodiment, the method further comprises:

-   -   when the left block of the current coding block is available and        a value corresponding to an intra mode of the left block is in a        second predefined range (in an example, the range could be from        35 to 66, which include 35 and 66), adding a vertical mode into        a MPM list of the current coding block (in an example, before        this adding operation, the MPM list of the current coding block        may be an empty list).

In an embodiment, the method further comprises:

-   -   determining whether an above block (for example, block A in FIG.        6 ) of the current coding block is available or not (for        example, if there is no intra prediction mode of the above        block, the above block is not available, if there is an intra        prediction mode of the above block, the above block is        available),    -   when the above block of the current coding block is not        available, adding a Planar mode into a MPM list of the current        coding block (in an example, before this adding operation, the        MPM list of the current coding block comprises one intra mode.        After this adding process, the MPM list comprises two intra        modes, for example, the MPM list may comprises (0, 0) or (1, 0)        or (50, 0) or (18, 0)).

In an embodiment, the method further comprises:

-   -   determining whether an above block (for example, block A in FIG.        6 ) of the current coding block is available or not (for        example, if there is no intra prediction mode of the above        block, the above block is not available, if there is an intra        prediction mode of the above block, the above block is        available),    -   when the above block of the current coding block is not        available and a Planar mode is not comprised in the MPM list of        the current coding block (in an example, when an intra mode of        the left block is DC mode or angular mode, a Planar mode is not        comprised in the MPM list after the first intra mode is added        into the MPM list), adding a Planar mode into a MPM list of the        current coding block (in an example, before this adding        operation, the MPM list of the current coding block comprises        one intra mode. After this adding process, the MPM list        comprises two intra modes, for example, the MPM list may        comprises (1, 0) or (50, 0) or (18, 0)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available        and an intra mode of the above block is Planar mode, adding a        Planar mode into a MPM list of the current coding block (in an        example, before this adding operation, the MPM list of the        current coding block comprises one intra mode. After this adding        process, the MPM list comprises two intra modes, for example,        the MPM list may comprises (0, 0) or (1, 0) or (50, 0) or (18,        0)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available,        an intra mode of the above block is Planar mode and a Planar        mode is not comprised in the MPM list of the current coding        block (in an example, when an intra mode of the left block is DC        mode or angular mode, a Planar mode is not comprised in the MPM        list after the first intra mode is added into the MPM list),        adding a Planar mode into a MPM list of the current coding block        (in an example, before this adding operation, the MPM list of        the current coding block comprises one intra mode. After this        adding process, the MPM list comprises two intra modes, for        example, the MPM list may comprises (1, 0) or (50, 0) or (18,        0)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available        and an intra mode of the above block is DC mode, adding a DC        mode into a MPM list of the current coding block (in an example,        before this adding operation, the MPM list of the current coding        block comprises one intra mode. After this adding process, the        MPM list comprises two intra modes, for example, the MPM list        may comprises (0, 1) or (1, 1) or (50, 1) or (18, 1)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available,        an intra mode of the above block is DC mode and a DC mode is not        comprised in the MPM list of the current coding block (in an        example, when an intra mode of the left block is not a DC mode,        a DC mode is not comprised in the MPM list after the first intra        mode is added into the MPM list), adding a DC mode into a MPM        list of the current coding block (in an example, before this        adding operation, the MPM list of the current coding block        comprises one intra mode. After this adding process, the MPM        list comprises two intra modes, for example, the MPM list may        comprises (0, 1) or (50, 1) or (18, 1)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available        and a value corresponding to an intra mode of the above block is        in a first predefined range (in an example, the range could be        from 2 to 34, which include 2 and 34), adding a horizontal mode        into a MPM list of the current coding block (in an example,        before this adding operation, the MPM list of the current coding        block comprises one intra mode. After this adding process, the        MPM list comprises two intra modes, for example, the MPM list        may comprises (0, 18) or (1, 18) or (50, 18) or (18, 18)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available, a        value corresponding to an intra mode of the above block is in a        first predefined range (in an example, the range could be from 2        to 34, which include 2 and 34), and a horizontal mode is not        comprised in the MPM list of the current coding block (in an        example, when an intra mode of the left block is DC mode or        Planar mode or a value corresponding to the intra mode of the        left block is not in the first predefined range, a horizontal        mode is not comprised in the MPM list after the first intra mode        is added into the MPM list), adding a horizontal mode into a MPM        list of the current coding block (in an example, before this        adding operation, the MPM list of the current coding block        comprises one intra mode. After this adding process, the MPM        list comprises two intra modes, for example, the MPM list may        comprises (0, 18) or (1, 18) or (50, 18)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available        and a value corresponding to an intra mode of the above block is        in a second predefined range (in an example, the range could be        from 35 to 66, which include 35 and 66), adding a vertical mode        into a MPM list of the current coding block (in an example,        before this adding operation, the MPM list of the current coding        block comprises one intra mode. After this adding process, the        MPM list comprises two intra modes, for example, the MPM list        may comprises (0, 50) or (1, 50) or (50, 50) or (18, 50)).

In an embodiment, the method further comprises:

-   -   when the above block of the current coding block is available, a        value corresponding to an intra mode of the above block is in a        second predefined range (in an example, the range could be from        35 to 66, which include 35 and 66) and a vertical mode is not        comprised in the MPM list of the current coding block (in an        example, when an intra mode of the left block is DC mode or        Planar mode or a value corresponding to the intra mode of the        left block is not in the second predefined range, a vertical        mode is not comprised in the MPM list after the first intra mode        is added into the MPM list), adding a vertical mode into a MPM        list of the current coding block (in an example, before this        adding operation, the MPM list of the current coding block        comprises one intra mode. After this adding process, the MPM        list comprises two intra modes, for example, the MPM list may        comprises (0, 50) or (1, 50) or (18, 50)).

In an embodiment, the method further comprises:

-   -   when a quantity of one or more intra modes in the MPM list of        the current coding block is less than a predefined value (for        example, the value may be 2, 3, or 4), and a Planar mode is not        comprised in the MPM list of the current coding block, adding a        Planar mode into the MPM list of the current coding block.

In an embodiment, the method further comprises:

-   -   when a quantity of one or more intra modes in the MPM list of        the current coding block is less than a predefined value (for        example, the value may be 2, 3, or 4), and a DC mode is not        comprised in the MPM list of the current coding block, adding a        DC mode into the MPM list of the current coding block.

In an embodiment, the method further comprises:

-   -   when a quantity of one or more intra modes in the MPM list of        the current coding block is less than a predefined value (for        example, the value may be 2, 3, or 4), and a vertical mode is        not comprised in the MPM list of the current coding block,        adding a vertical mode into the MPM list of the current coding        block.

In a an embodiment, the method further comprises:

-   -   when a quantity of one or more intra modes in the MPM list of        the current coding block is less than a predefined value (for        example, the value may be 2, 3, or 4), and a horizontal mode is        not comprised in the MPM list of the current coding block,        adding a horizontal mode into the MPM list of the current coding        block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   constructing a most probable mode, MPM, list for a current block        according to intra modes of neighboring blocks of the current        block (in one example, the MPM list of the current block        comprises six intra modes. In an example, one MPM list comprises        one or more intra modes means that the MPM list comprises one or        more values corresponding to one or more intra modes, one value        corresponding to one intra mode), wherein the MPM list comprises        one or more angular modes;    -   obtaining an indication parameter for the current block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        block or not;    -   obtaining an index parameter for the current block according to        the bitstream; when, according to a value of indication        parameter, the multi-hypothesis prediction is applied to the        current block,    -   obtaining an intra prediction mode for the current block        according to the index parameter and the MPM list of the current        block;    -   when a value corresponding to the intra prediction mode of the        current block is in a predefined range (in an example, the range        could be from 2 to 34, which include 2 and 34; or the range        could be from 35 to 66, which include 35 and 66), decoding the        current block according to a predefined mode (for example, the        predefined mode may be horizontal mode or vertical mode).

In an embodiment, the method further comprises when a valuecorresponding to the intra prediction mode of the current block is in arange 2 to 34 (which include 2 and 34), the predefined mode ishorizontal mode, or when a value corresponding to the intra predictionmode of the current block is in a range 2 to 33 (which include 2 and33), the predefined mode is horizontal mode.

In an embodiment, the method further comprises when a valuecorresponding to the intra prediction mode of the current block is in arange 35 to 66 (which include 35 and 66), the predefined mode isvertical mode, or when a value corresponding to the intra predictionmode of the current block is in a range 34 to 66 (which include 34 and66), the predefined mode is vertical mode.

In an embodiment, the method further comprises when the intra predictionmode of the current block is an angular mode (for example, a valuecorresponding to the intra prediction mode of the current block is in arange 2 to 66, which include 2 and 66), the predefined mode is Planarmode.

In an embodiment, the method further comprises when the intra predictionmode of the current block is an angular mode (for example, a valuecorresponding to the intra prediction mode of the current block is in arange 2 to 66, which include 2 and 66), the predefined mode is DC mode.

In an embodiment, the method further comprises when a valuecorresponding to the intra prediction mode of the current block is in arange 2 to 66 (which include 2 and 66), the predefined mode is verticalmode.

In an embodiment, the method further comprises when a valuecorresponding to the intra prediction mode of the current block is in arange 2 to 66 (which include 2 and 66), the predefined mode ishorizontal mode.

In an embodiment, the method further comprises when the intra predictionmode for the current block is Planar mode, decoding the current blockaccording to a Planar mode.

In an embodiment, the method further comprises when the intra predictionmode for the current block is DC mode, decoding the current blockaccording to a DC mode.

In an embodiment, the method further comprises when the intra predictionmode for the current block is DC mode, decoding the current blockaccording to a Planar mode.

In an embodiment, the method further comprises the index parameter has amaximum value of N, where N is smaller than the size of the MPM list, Nis positive integer.

In an embodiment, the method further comprises N is equal to 1 (theindex parameter can have a value of either a 0 or 1).

In an embodiment, the method further comprises N is equal to 3 (theindex parameter can have a value of either a 0, 1, 2 or 3).

In an embodiment, the method further comprises the index parameter ispredefined and equal to 0, which indicates the first candidate in theMPM list.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   obtaining an index parameter for the current coding block        according to the bitstream;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block, obtaining an intra prediction mode for the current coding        block according to the index parameter and a predefined list,        wherein the predefined list comprises the following intra        prediction modes orderly: planar mode, Horizontal mode, and        Vertical mode; and    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture (or a frame) implemented by a decodingdevice, comprising:

-   -   obtaining an indication parameter for a current coding block        according to a bitstream, the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block or not;    -   obtaining an index parameter for the current coding block        according to the bitstream;    -   when, according to a value of indication parameter, the        multi-hypothesis prediction is applied to the current coding        block, obtaining an intra prediction mode for the current coding        block according to the index parameter and a predefined list,        wherein the predefined list comprises the following intra        prediction modes orderly: planar mode, Vertical mode, and        Horizontal mode; and    -   decoding the current coding block according to the intra        prediction mode for the current coding block.

According to an embodiment, the disclosure relates to a method ofdecoding a block of a picture, comprising:

-   -   obtaining an indication parameter for a current coding block,        wherein the indication parameter represents whether a        multi-hypothesis prediction is applied to the current coding        block;    -   when the indication parameter represents that the        multi-hypothesis prediction is applied to the current coding        block; decoding the current coding block according to a planar        mode.

In an embodiment, the multi-hypothesis prediction is a combined interand intra prediction (CIIP).

In an embodiment, the indication parameter is CIIP flag.

In an embodiment, the indication parameter is carried by merge datasyntax.

In an embodiment, the method further comprises: obtaining the planarmode for the current coding block according to a most probable mode(MPM) list, wherein each of the intra prediction mode in the MPM list isindexed with a corresponding value of MPM list index.

In an embodiment, the method further comprises:

-   -   parsing a bitstream to obtain a MPM list index, wherein the MPM        list index has value between 0 to N−1, and wherein N is the        entries of the intra prediction modes in the MPM list; and        obtaining the intra prediction mode for the current coding block        from the MPM list according to the value of the MPM list index.

In a an embodiment, the MPM list comprises at least planar mode.

In an embodiment, the MPM list comprises planar mode and at least one ofDC mode, vertical mode and horizontal mode.

In an embodiment, the MPM list consist of planar mode.

In an embodiment, the MPM list is constructed from a pre-defined defaultlist.

In an embodiment, the MPM list index is coded into decimal or binaryrepresentation.

In an embodiment, a decoder comprising a processing circuitry forcarrying out the method according to any preceding implementation of theforty-third aspect.

In an embodiment, a decoder, comprising: a memory storage comprisinginstructions; and

-   -   one or more processors in communication with the memory, wherein        the one or more processors execute the instructions to carry out        the method according to any preceding implementation of the        forty-third aspect.

According to an embodiment, the disclosure relates to an apparatus fordecoding, the apparatus comprising: a determining unit configured toobtain an indication parameter for a current coding block, wherein theindication parameter represents whether a multi-hypothesis prediction isapplied to the current coding block; and an intra prediction processingunit configured to perform intra prediction for the current coding blockbased on a planar mode when the indication parameter represents that themulti-hypothesis prediction is applied to the current coding block.

In an embodiment, wherein the apparatus further comprises a parsingunit, configured to parse a plurality of syntax elements from abitstream of a video signal; the determining unit further configured todetermine the planar mode based on a syntax element from the pluralityof syntax elements.

According to an embodiment, the disclosure relates to a method ofencoding a block of a picture, comprising: obtaining an indicationparameter for a current block, wherein the indication parameterrepresents whether a multi-hypothesis prediction is applied to thecurrent block; when the indication parameter represents that themulti-hypothesis prediction is applied to the current block, encodingthe current block according to a planar mode.

In an embodiment, the multi-hypothesis prediction is a combined interand intra prediction (CIIP).

In an embodiment, the indication parameter is CIIP flag.

In an embodiment, the indication parameter is carried by merge datasyntax.

In an embodiment, the method further comprises:

-   -   obtaining the planar mode for the current coding block according        to a most probable mode (MPM) list, wherein each of the intra        prediction mode in the MPM list is indexed with a corresponding        value of MPM list index.

In an embodiment, the method further comprises: indexing each of theintra prediction mode in the MPM list with a corresponding value of MPMlist index; parsing the MPM list index from a bitstream, wherein the MPMlist index has value between 0 to N−1, wherein N is the entries of theintra prediction modes in the MPM list. Obtaining the intra predictionmode of the current coding block from the MPM list according to thevalue of the MPM list index.

In an embodiment, the MPM list comprises at least planar mode.

In an embodiment, the MPM list comprises planar mode and at least one ofDC mode, vertical mode and horizontal mode.

In an embodiment, the MPM list consist of planar mode.

In an embodiment, the MPM list is constructed from a pre-defined defaultlist.

In an embodiment, the MPM list index is coded into decimal or binaryrepresentation.

In an embodiment, an encoder comprising a processing circuitry forcarrying out the method according to any preceding implementation of theforty-fifth aspect.

In an embodiment, an encoder comprising a memory storage comprisinginstructions; and

-   -   one or more processors in communication with the memory, wherein        the one or more processors execute the instructions to carry out        the method according to any preceding implementation of the        forty-fifth aspect.

In an embodiment, a computer program product comprising program code forperforming the method of any preceding implementation of the forty-fifthaspect when executed on a computer or a processor.

According to an embodiment, the disclosure relates to an apparatus forencoding a block of a picture, the apparatus comprising: a determiningunit configured to obtain an indication parameter for a current block,wherein the indication parameter represents whether a multi-hypothesisprediction is applied to the current block; and an intra predictionprocessing unit configured to encode the current block according to aplanar mode when the indication parameter represents that themulti-hypothesis prediction is applied to the current block.

Details of one or more embodiments are set forth in the accompanyingdrawings and the description below. Other features, objects, andadvantages will be apparent from the description, drawings, and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following embodiments of the disclosure are described in moredetail with reference to the attached figures and drawings, in which:

FIG. 1A is a block diagram showing an example of a video coding systemconfigured to implement embodiments of the disclosure;

FIG. 1B is a block diagram showing another example of a video codingsystem configured to implement embodiments of the disclosure;

FIG. 2 is a block diagram showing an example of a video encoderconfigured to implement embodiments of the disclosure;

FIG. 3 is a block diagram showing an example structure of a videodecoder configured to implement embodiments of the disclosure;

FIG. 4 is a block diagram illustrating an example of an encodingapparatus or a decoding apparatus;

FIG. 5 is a block diagram illustrating another example of an encodingapparatus or a decoding apparatus;

FIG. 6 is an example illustrating neighboring blocks of a current codingblock or coding unit.

FIG. 7 is an example showing many intra prediction modes.

FIG. 8 is an example illustrating a method of decoding a block of apicture.

FIG. 9 is a block diagram showing an example structure of a contentsupply system 3100 which realizes a content delivery service.

FIG. 10 is a block diagram showing a structure of an example of aterminal device.

In the following identical reference signs refer to identical or atleast functionally equivalent features if not explicitly specifiedotherwise.

DETAILED DESCRIPTION OF THE EMBODIMENTS

In the following description, reference is made to the accompanyingfigures, which form part of the disclosure, and which show, by way ofillustration, specific aspects of embodiments of the disclosure orspecific aspects in which embodiments of the present disclosure may beused. It is understood that embodiments of the disclosure may be used inother aspects and comprise structural or logical changes not depicted inthe figures. The following detailed description, therefore, is not to betaken in a limiting sense, and the scope of the present disclosure isdefined by the appended claims.

For instance, it is understood that a disclosure in connection with adescribed method may also hold true for a corresponding device or systemconfigured to perform the method and vice versa. For example, if one ora plurality of specific method operations are described, a correspondingdevice may include one or a plurality of units, e.g., functional units,to perform the described one or plurality of method operations (e.g.,one unit performing the one or plurality of operations, or a pluralityof units each performing one or more of the plurality of operations),even if such one or more units are not explicitly described orillustrated in the figures. On the other hand, for example, if aspecific apparatus is described based on one or a plurality of units,e.g., functional units, a corresponding method may include one operationto perform the functionality of the one or plurality of units (e.g., oneoperation performing the functionality of the one or plurality of units,or a plurality of operations each performing the functionality of one ormore of the plurality of units), even if such one or plurality ofoperations are not explicitly described or illustrated in the figures.Further, it is understood that the features of the various exemplaryembodiments and/or aspects described herein may be combined with eachother, unless specifically noted otherwise.

Video coding typically refers to the processing of a sequence ofpictures, which form the video or video sequence. Instead of the term“picture” the term “frame” or “image” may be used as synonyms in thefield of video coding. Video coding (or coding in general) comprises twoparts video encoding and video decoding. Video encoding is performed atthe source side, typically comprising processing (e.g., by compression)the original video pictures to reduce the amount of data required forrepresenting the video pictures (for more efficient storage and/ortransmission). Video decoding is performed at the destination side andtypically comprises the inverse processing compared to the encoder toreconstruct the video pictures. Embodiments referring to “coding” ofvideo pictures (or pictures in general) shall be understood to relate to“encoding” or “decoding” of video pictures or respective videosequences. The combination of the encoding part and the decoding part isalso referred to as CODEC (Coding and Decoding).

In case of lossless video coding, the original video pictures can bereconstructed, e.g., the reconstructed video pictures have the samequality as the original video pictures (assuming no transmission loss orother data loss during storage or transmission). In case of lossy videocoding, further compression, e.g., by quantization, is performed, toreduce the amount of data representing the video pictures, which cannotbe completely reconstructed at the decoder, e.g., the quality of thereconstructed video pictures is lower or worse compared to the qualityof the original video pictures.

Several video coding standards belong to the group of “lossy hybridvideo codecs” (e.g., combine spatial and temporal prediction in thesample domain and 2D transform coding for applying quantization in thetransform domain). Each picture of a video sequence is typicallypartitioned into a set of non-overlapping blocks and the coding istypically performed on a block level. In other words, at the encoder thevideo is typically processed, e.g., encoded, on a block (video block)level, e.g., by using spatial (intra picture) prediction and/or temporal(inter picture) prediction to generate a prediction block, subtractingthe prediction block from the current block (block currentlyprocessed/to be processed) to obtain a residual block, transforming theresidual block and quantizing the residual block in the transform domainto reduce the amount of data to be transmitted (compression), whereas atthe decoder the inverse processing compared to the encoder is applied tothe encoded or compressed block to reconstruct the current block forrepresentation. Furthermore, the encoder duplicates the decoderprocessing loop such that both will generate identical predictions(e.g., intra- and inter predictions) and/or re-constructions forprocessing, e.g., coding, the subsequent blocks.

In the following embodiments of a video coding system 10, a videoencoder 20 and a video decoder 30 are described based on FIGS. 1 to 3 .

FIG. 1A is a schematic block diagram illustrating an example codingsystem 10, e.g., a video coding system 10 (or short coding system 10)that may utilize techniques of this present disclosure. Video encoder 20(or short encoder 20) and video decoder 30 (or short decoder 30) ofvideo coding system 10 represent examples of devices that may beconfigured to perform techniques in accordance with various examplesdescribed in the present disclosure.

As shown in FIG. 1A, the coding system 10 comprises a source device 12configured to provide encoded picture data 21 e.g., to a destinationdevice 14 for decoding the encoded picture data 13.

The source device 12 comprises an encoder 20, and may additionallycomprise a picture source 16, a pre-processor (or pre-processing unit)18, e.g., a picture pre-processor 18, and a communication interface orcommunication unit 22 in an embodiment.

The picture source 16 may comprise or be any kind of picture capturingdevice, for example a camera for capturing a real-world picture, and/orany kind of a picture generating device, for example a computer-graphicsprocessor for generating a computer animated picture, or any kind ofother device for obtaining and/or providing a real-world picture, acomputer generated picture (e.g., a screen content, a virtual reality(VR) picture) and/or any combination thereof (e.g., an augmented reality(AR) picture). The picture source may be any kind of memory or storagestoring any of the aforementioned pictures.

In distinction to the pre-processor 18 and the processing performed bythe pre-processing unit 18, the picture or picture data 17 may also bereferred to as raw picture or raw picture data 17.

Pre-processor 18 is configured to receive the (raw) picture data 17 andto perform pre-processing on the picture data 17 to obtain apre-processed picture 19 or pre-processed picture data 19.Pre-processing performed by the pre-processor 18 may, e.g., comprisetrimming, color format conversion (e.g., from RGB to YCbCr), colorcorrection, or de-noising. It can be understood that the pre-processingunit 18 may be optional component.

The video encoder 20 is configured to receive the pre-processed picturedata 19 and provide encoded picture data 21 (further details will bedescribed below, e.g., based on FIG. 2 ).

Communication interface 22 of the source device 12 may be configured toreceive the encoded picture data 21 and to transmit the encoded picturedata 21 (or any further processed version thereof) over communicationchannel 13 to another device, e.g., the destination device 14 or anyother device, for storage or direct reconstruction.

The destination device 14 comprises a decoder 30 (e.g., a video decoder30), and may additionally comprise a communication interface orcommunication unit 28, a post-processor 32 (or post-processing unit 32)and a display device 34 in an embodiment.

The communication interface 28 of the destination device 14 isconfigured receive the encoded picture data 21 (or any further processedversion thereof), e.g., directly from the source device 12 or from anyother source, e.g., a storage device, e.g., an encoded picture datastorage device, and provide the encoded picture data 21 to the decoder30.

The communication interface 22 and the communication interface 28 may beconfigured to transmit or receive the encoded picture data 21 or encodeddata 13 via a direct communication link between the source device 12 andthe destination device 14, e.g., a direct wired or wireless connection,or via any kind of network, e.g., a wired or wireless network or anycombination thereof, or any kind of private and public network, or anykind of combination thereof.

The communication interface 22 may be, e.g., configured to package theencoded picture data 21 into an appropriate format, e.g., packets,and/or process the encoded picture data using any kind of transmissionencoding or processing for transmission over a communication link orcommunication network.

The communication interface 28, forming the counterpart of thecommunication interface 22, may be, e.g., configured to receive thetransmitted data and process the transmission data using any kind ofcorresponding transmission decoding or processing and/or de-packaging toobtain the encoded picture data 21.

Both, communication interface 22 and communication interface 28 may beconfigured as unidirectional communication interfaces as indicated bythe arrow for the communication channel 13 in FIG. 1A pointing from thesource device 12 to the destination device 14, or bi-directionalcommunication interfaces, and may be configured, e.g., to send andreceive messages, e.g., to set up a connection, to acknowledge andexchange any other information related to the communication link and/ordata transmission, e.g., encoded picture data transmission.

The decoder 30 is configured to receive the encoded picture data 21 andprovide decoded picture data 31 or a decoded picture 31 (further detailswill be described below, e.g., based on FIG. 3 or FIG. 5 ).

The post-processor 32 of destination device 14 is configured topost-process the decoded picture data 31 (also called reconstructedpicture data), e.g., the decoded picture 31, to obtain post-processedpicture data 33, e.g., a post-processed picture 33. The post-processingperformed by the post-processing unit 32 may comprise, e.g., colorformat conversion (e.g., from YCbCr to RGB), color correction, trimming,or re-sampling, or any other processing, e.g., for preparing the decodedpicture data 31 for display, e.g., by display device 34.

The display device 34 of the destination device 14 is configured toreceive the post-processed picture data 33 for displaying the picture,e.g., to a user or viewer. The display device 34 may be or comprise anykind of display for representing the reconstructed picture, e.g., anintegrated or external display or monitor. The displays may, e.g.,comprise liquid crystal displays (LCD), organic light emitting diodes(OLED) displays, plasma displays, projectors, micro LED displays, liquidcrystal on silicon (LCoS), digital light processor (DLP) or any kind ofother display.

Although FIG. 1A depicts the source device 12 and the destination device14 as separate devices, embodiments of devices may also comprise both orboth functionalities, the source device 12 or correspondingfunctionality and the destination device 14 or correspondingfunctionality. In such embodiments the source device 12 or correspondingfunctionality and the destination device 14 or correspondingfunctionality may be implemented using the same hardware and/or softwareor by separate hardware and/or software or any combination thereof.

As will be apparent for the skilled person based on the description, theexistence and (exact) split of functionalities of the different units orfunctionalities within the source device 12 and/or destination device 14as shown in FIG. 1A may vary depending on the actual device andapplication.

The encoder 20 (e.g., a video encoder 20) or the decoder 30 (e.g., avideo decoder or both encoder 20 and decoder 30 may be implemented viaprocessing circuitry as shown in FIG. 1B, such as one or moremicroprocessors, digital signal processors (DSPs), application-specificintegrated circuits (ASICs), field-programmable gate arrays (FPGAs),discrete logic, hardware, video coding dedicated or any combinationsthereof. The encoder 20 may be implemented via processing circuitry 46to embody the various modules as discussed with respect to encoder 20 ofFIG. 2 and/or any other encoder system or subsystem described herein.The decoder 30 may be implemented via processing circuitry 46 to embodythe various modules as discussed with respect to decoder 30 of FIG. 3and/or any other decoder system or subsystem described herein. Theprocessing circuitry may be configured to perform the various operationsas discussed later. As shown in FIG. 5 , if the techniques areimplemented partially in software, a device may store instructions forthe software in a suitable, non-transitory computer-readable storagemedium and may execute the instructions in hardware using one or moreprocessors to perform the techniques of this disclosure. Either of videoencoder 20 and video decoder 30 may be integrated as part of a combinedencoder/decoder (CODEC) in a single device, for example, as shown inFIG. 1B.

Source device 12 and destination device 14 may comprise any of a widerange of devices, including any kind of handheld or stationary devices,e.g., notebook or laptop computers, mobile phones, smart phones, tabletsor tablet computers, cameras, desktop computers, set-top boxes,televisions, display devices, digital media players, video gamingconsoles, video streaming devices (such as content services servers orcontent delivery servers), broadcast receiver device, broadcasttransmitter device, or the like and may use no or any kind of operatingsystem. In some cases, the source device 12 and the destination device14 may be equipped for wireless communication. Thus, the source device12 and the destination device 14 may be wireless communication devices.

In some cases, video coding system 10 illustrated in FIG. 1A is merelyan example and the techniques of the present disclosure may apply tovideo coding settings (e.g., video encoding or video decoding) that donot necessarily include any data communication between the encoding anddecoding devices. In other examples, data is retrieved from a localmemory, streamed over a network, or the like. A video encoding devicemay encode and store data to memory, and/or a video decoding device mayretrieve and decode data from memory. In some examples, the encoding anddecoding is performed by devices that do not communicate with oneanother, but simply encode data to memory and/or retrieve and decodedata from memory.

For convenience of description, embodiments of the disclosure aredescribed herein, for example, by reference to High-Efficiency VideoCoding (HEVC) or to the reference software of Versatile Video coding(VVC), the next generation video coding standard developed by the JointCollaboration Team on Video Coding (JCT-VC) of ITU-T Video CodingExperts Group (VCEG) and ISO/IEC Motion Picture Experts Group (MPEG).One of ordinary skill in the art will understand that embodiments of thedisclosure are not limited to HEVC or VVC.

Encoder and Encoding Method

FIG. 2 shows a schematic block diagram of an example video encoder 20that is configured to implement the techniques of the presentdisclosure. In the example of FIG. 2 , the video encoder 20 comprises aninput 201 (or input interface 201), a residual calculation unit 204, atransform processing unit 206, a quantization unit 208, an inversequantization unit 210, and inverse transform processing unit 212, areconstruction unit 214, a loop filter unit 220, a decoded picturebuffer (DPB) 230, a mode selection unit 260, an entropy encoding unit270 and an output 272 (or output interface 272). The mode selection unit260 may include an inter prediction unit 244, an intra prediction unit254 and a partitioning unit 262. Inter prediction unit 244 may include amotion estimation unit and a motion compensation unit (not shown). Avideo encoder 20 as shown in FIG. 2 may also be referred to as hybridvideo encoder or a video encoder according to a hybrid video codec.

The residual calculation unit 204, the transform processing unit 206,the quantization unit 208, the mode selection unit 260 may be referredto as forming a forward signal path of the encoder 20, whereas theinverse quantization unit 210, the inverse transform processing unit212, the reconstruction unit 214, the buffer 216, the loop filter 220,the decoded picture buffer (DPB) 230, the inter prediction unit 244 andthe intra-prediction unit 254 may be referred to as forming a backwardsignal path of the video encoder 20, wherein the backward signal path ofthe video encoder 20 corresponds to the signal path of the decoder (seevideo decoder 30 in FIG. 3 ). The inverse quantization unit 210, theinverse transform processing unit 212, the reconstruction unit 214, theloop filter 220, the decoded picture buffer (DPB) 230, the interprediction unit 244 and the intra-prediction unit 254 are also referredto forming the “built-in decoder” of video encoder 20.

Pictures & Picture Partitioning (Pictures & Blocks)

The encoder 20 may be configured to receive, e.g., via input 201, apicture 17 (or picture data 17), e.g., picture of a sequence of picturesforming a video or video sequence. The received picture or picture datamay also be a pre-processed picture 19 (or pre-processed picture data19). For sake of simplicity the following description refers to thepicture 17. The picture 17 may also be referred to as current picture orpicture to be coded (in particular in video coding to distinguish thecurrent picture from other pictures, e.g., previously encoded and/ordecoded pictures of the same video sequence, e.g., the video sequencewhich also comprises the current picture).

A (digital) picture is or can be regarded as a two-dimensional array ormatrix of samples with intensity values. A sample in the array may alsobe referred to as pixel (short form of picture element) or a pel. Thenumber of samples in horizontal and vertical direction (or axis) of thearray or picture define the size and/or resolution of the picture. Forrepresentation of color, typically three color components are employed,e.g., the picture may be represented or include three sample arrays. InRBG format or color space a picture comprises a corresponding red, greenand blue sample array. However, in video coding each pixel is typicallyrepresented in a luminance and chrominance format or color space, e.g.,YCbCr, which comprises a luminance component indicated by Y (sometimesalso L is used instead) and two chrominance components indicated by Cband Cr. The luminance (or short luma) component Y represents thebrightness or grey level intensity (e.g., like in a grey-scale picture),while the two chrominance (or short chroma) components Cb and Crrepresent the chromaticity or color information components. Accordingly,a picture in YCbCr format comprises a luminance sample array ofluminance sample values (Y), and two chrominance sample arrays ofchrominance values (Cb and Cr). Pictures in RGB format may be convertedor transformed into YCbCr format and vice versa, the process is alsoknown as color transformation or conversion. If a picture is monochrome,the picture may comprise only a luminance sample array. Accordingly, apicture may be, for example, an array of luma samples in monochromeformat or an array of luma samples and two corresponding arrays ofchroma samples in 4:2:0, 4:2:2, and 4:4:4 color format.

Embodiments of the video encoder 20 may comprise a picture partitioningunit (not depicted in FIG. 2 ) configured to partition the picture 17into a plurality of (typically non-overlapping) picture blocks 203.These blocks may also be referred to as root blocks, macro blocks(H.264/AVC) or coding tree blocks (CTB) or coding tree units (CTU)(H.265/HEVC and VVC). The picture partitioning unit may be configured touse the same block size for all pictures of a video sequence and thecorresponding grid defining the block size, or to change the block sizebetween pictures or subsets or groups of pictures, and partition eachpicture into the corresponding blocks.

In further embodiments, the video encoder may be configured to receivedirectly a block 203 of the picture 17, e.g., one, several or all blocksforming the picture 17. The picture block 203 may also be referred to ascurrent picture block or picture block to be coded.

Like the picture 17, the picture block 203 again is or can be regardedas a two-dimensional array or matrix of samples with intensity values(sample values), although of smaller dimension than the picture 17. Inother words, the block 203 may comprise, e.g., one sample array (e.g., aluma array in case of a monochrome picture 17, or a luma or chroma arrayin case of a color picture) or three sample arrays (e.g., a luma and twochroma arrays in case of a color picture 17) or any other number and/orkind of arrays depending on the color format applied. The number ofsamples in horizontal and vertical direction (or axis) of the block 203define the size of block 203. Accordingly, a block may, for example, anM×N (M-column by N-row) array of samples, or an M×N array of transformcoefficients.

Embodiments of the video encoder 20 as shown in FIG. 2 may be configuredencode the picture 17 block by block, e.g., the encoding and predictionis performed per block 203.

Residual Calculation

The residual calculation unit 204 may be configured to calculate aresidual block 205 (also referred to as residual 205) based on thepicture block 203 and a prediction block 265 (further details about theprediction block 265 are provided later), e.g., by subtracting samplevalues of the prediction block 265 from sample values of the pictureblock 203, sample by sample (pixel by pixel) to obtain the residualblock 205 in the sample domain.

Transform

The transform processing unit 206 may be configured to apply atransform, e.g., a discrete cosine transform (DCT) or discrete sinetransform (DST), on the sample values of the residual block 205 toobtain transform coefficients 207 in a transform domain. The transformcoefficients 207 may also be referred to as transform residualcoefficients and represent the residual block 205 in the transformdomain.

The transform processing unit 206 may be configured to apply integerapproximations of DCT/DST, such as the transforms specified forH.265/HEVC. Compared to an orthogonal DCT transform, such integerapproximations are typically scaled by a certain factor. In order topreserve the norm of the residual block which is processed by forwardand inverse transforms, additional scaling factors are applied as partof the transform process. The scaling factors are typically chosen basedon certain constraints like scaling factors being a power of two forshift operations, bit depth of the transform coefficients, tradeoffbetween accuracy and implementation costs, etc. Specific scaling factorsare, for example, specified for the inverse transform, e.g., by inversetransform processing unit 212 (and the corresponding inverse transform,e.g., by inverse transform processing unit 312 at video decoder 30) andcorresponding scaling factors for the forward transform, e.g., bytransform processing unit 206, at an encoder 20 may be specifiedaccordingly.

Embodiments of the video encoder 20 (respectively transform processingunit 206) may be configured to output transform parameters, e.g., a typeof transform or transforms, e.g., directly or encoded or compressed viathe entropy encoding unit 270, so that, e.g., the video decoder 30 mayreceive and use the transform parameters for decoding.

Quantization

The quantization unit 208 may be configured to quantize the transformcoefficients 207 to obtain quantized coefficients 209, e.g., by applyingscalar quantization or vector quantization. The quantized coefficients209 may also be referred to as quantized transform coefficients 209 orquantized residual coefficients 209.

The quantization process may reduce the bit depth associated with someor all of the transform coefficients 207. For example, an n-bittransform coefficient may be rounded down to an m-bit Transformcoefficient during quantization, where n is greater than m. The degreeof quantization may be modified by adjusting a quantization parameter(QP). For example for scalar quantization, different scaling may beapplied to achieve finer or coarser quantization. Smaller quantizationstep sizes correspond to finer quantization, whereas larger quantizationstep sizes correspond to coarser quantization. The applicablequantization step size may be indicated by a quantization parameter(QP). The quantization parameter may for example be an index to apredefined set of applicable quantization step sizes. For example, smallquantization parameters may correspond to fine quantization (smallquantization step sizes) and large quantization parameters maycorrespond to coarse quantization (large quantization step sizes) orvice versa. The quantization may include division by a quantization stepsize and a corresponding and/or the inverse dequantization, e.g., byinverse quantization unit 210, may include multiplication by thequantization step size. Embodiments according to some standards, e.g.,HEVC, may be configured to use a quantization parameter to determine thequantization step size. Generally, the quantization step size may becalculated based on a quantization parameter using a fixed pointapproximation of an equation including division. Additional scalingfactors may be introduced for quantization and dequantization to restorethe norm of the residual block, which might get modified because of thescaling used in the fixed point approximation of the equation forquantization step size and quantization parameter. In one exampleimplementation, the scaling of the inverse transform and dequantizationmight be combined. Alternatively, customized quantization tables may beused and signaled from an encoder to a decoder, e.g., in a bitstream.The quantization is a lossy operation, wherein the loss increases withincreasing quantization step sizes.

Embodiments of the video encoder 20 (respectively quantization unit 208)may be configured to output quantization parameters (QP), e.g., directlyor encoded via the entropy encoding unit 270, so that, e.g., the videodecoder 30 may receive and apply the quantization parameters fordecoding.

Inverse Quantization

The inverse quantization unit 210 is configured to apply the inversequantization of the quantization unit 208 on the quantized coefficientsto obtain dequantized coefficients 211, e.g., by applying the inverse ofthe quantization scheme applied by the quantization unit 208 based on orusing the same quantization step size as the quantization unit 208. Thedequantized coefficients 211 may also be referred to as dequantizedresidual coefficients 211 and correspond—although typically notidentical to the transform coefficients due to the loss byquantization—to the transform coefficients 207.

Inverse Transform

The inverse transform processing unit 212 is configured to apply theinverse transform of the transform applied by the transform processingunit 206, e.g., an inverse discrete cosine transform (DCT) or inversediscrete sine transform (DST) or other inverse transforms, to obtain areconstructed residual block 213 (or corresponding dequantizedcoefficients 213) in the sample domain. The reconstructed residual block213 may also be referred to as transform block 213.

Reconstruction

The reconstruction unit 214 (e.g., adder or summer 214) is configured toadd the transform block 213 (e.g., reconstructed residual block 213) tothe prediction block 265 to obtain a reconstructed block 215 in thesample domain, e.g., by adding—sample by sample—the sample values of thereconstructed residual block 213 and the sample values of the predictionblock 265.

Filtering

The loop filter unit 220 (or short “loop filter” 220), is configured tofilter the reconstructed block 215 to obtain a filtered block 221, or ingeneral, to filter reconstructed samples to obtain filtered samples. Theloop filter unit is, e.g., configured to smooth pixel transitions, orotherwise improve the video quality. The loop filter unit 220 maycomprise one or more loop filters such as a de-blocking filter, asample-adaptive offset (SAO) filter or one or more other filters, e.g.,a bilateral filter, an adaptive loop filter (ALF), a sharpening, asmoothing filters or a collaborative filters, or any combinationthereof. Although the loop filter unit 220 is shown in FIG. 2 as beingan in loop filter, in other configurations, the loop filter unit 220 maybe implemented as a post loop filter. The filtered block 221 may also bereferred to as filtered reconstructed block 221.

Embodiments of the video encoder 20 (respectively loop filter unit 220)may be configured to output loop filter parameters (such as sampleadaptive offset information), e.g., directly or encoded via the entropyencoding unit 270, so that, e.g., a decoder 30 may receive and apply thesame loop filter parameters or respective loop filters for decoding.

Decoded Picture Buffer

The decoded picture buffer (DPB) 230 may be a memory that storesreference pictures, or in general reference picture data, for encodingvideo data by video encoder 20. The DPB 230 may be formed by any of avariety of memory devices, such as dynamic random access memory (DRAM),including synchronous DRAM (SDRAM), magnetoresistive RAM (MRAM),resistive RAM (RRAM), or other types of memory devices. The decodedpicture buffer (DPB) 230 may be configured to store one or more filteredblocks 221. The decoded picture buffer 230 may be further configured tostore other previously filtered blocks, e.g., previously reconstructedand filtered blocks 221, of the same current picture or of differentpictures, e.g., previously reconstructed pictures, and may providecomplete previously reconstructed, e.g., decoded, pictures (andcorresponding reference blocks and samples) and/or a partiallyreconstructed current picture (and corresponding reference blocks andsamples), for example for inter prediction. The decoded picture buffer(DPB) 230 may be also configured to store one or more unfilteredreconstructed blocks 215, or in general unfiltered reconstructedsamples, e.g., if the reconstructed block 215 is not filtered by loopfilter unit 220, or any other further processed version of thereconstructed blocks or samples.

Mode Selection (Partitioning & Prediction)

The mode selection unit 260 comprises partitioning unit 262,inter-prediction unit 244 and intra-prediction unit 254, and isconfigured to receive or obtain original picture data, e.g., an originalblock 203 (current block 203 of the current picture 17), andreconstructed picture data, e.g., filtered and/or unfilteredreconstructed samples or blocks of the same (current) picture and/orfrom one or a plurality of previously decoded pictures, e.g., fromdecoded picture buffer 230 or other buffers (e.g., line buffer, notshown). The reconstructed picture data is used as reference picture datafor prediction, e.g., inter-prediction or intra-prediction, to obtain aprediction block 265 or predictor 265.

Mode selection unit 260 may be configured to determine or select apartitioning for a current block prediction mode (including nopartitioning) and a prediction mode (e.g., an intra or inter predictionmode) and generate a corresponding prediction block 265, which is usedfor the calculation of the residual block 205 and for the reconstructionof the reconstructed block 215.

Embodiments of the mode selection unit 260 may be configured to selectthe partitioning and the prediction mode (e.g., from those supported byor available for mode selection unit 260), which provide the best matchor in other words the minimum residual (minimum residual means bettercompression for transmission or storage), or a minimum signalingoverhead (minimum signaling overhead means better compression fortransmission or storage), or which considers or balances both. The modeselection unit 260 may be configured to determine the partitioning andprediction mode based on rate distortion optimization (RDO), e.g.,select the prediction mode which provides a minimum rate distortion.Terms like “best”, “minimum”, “optimum” etc. in this context do notnecessarily refer to an overall “best”, “minimum”, “optimum”, etc. butmay also refer to the fulfillment of a termination or selectioncriterion like a value exceeding or falling below a threshold or otherconstraints leading potentially to a “sub-optimum selection” butreducing complexity and processing time.

In other words, the partitioning unit 262 may be configured to partitionthe block 203 into smaller block partitions or sub-blocks (which formagain blocks), e.g., iteratively using quad-tree-partitioning (QT),binary partitioning (BT) or triple-tree-partitioning (TT) or anycombination thereof, and to perform, e.g., the prediction for each ofthe block partitions or sub-blocks, wherein the mode selection comprisesthe selection of the tree-structure of the partitioned block 203 and theprediction modes are applied to each of the block partitions orsub-blocks.

In the following the partitioning (e.g., by partitioning unit 260) andprediction processing (by inter-prediction unit 244 and intra-predictionunit 254) performed by an example video encoder 20 will be explained inmore detail.

Partitioning

The partitioning unit 262 may partition (or split) a current block 203into smaller partitions, e.g., smaller blocks of square or rectangularsize. These smaller blocks (which may also be referred to as sub-blocks)may be further partitioned into even smaller partitions. This is alsoreferred to tree-partitioning or hierarchical tree-partitioning, whereina root block, e.g., at root tree-level 0 (hierarchy-level 0, depth 0),may be recursively partitioned, e.g., partitioned into two or moreblocks of a next lower tree-level, e.g., nodes at tree-level 1(hierarchy-level 1, depth 1), wherein these blocks may be againpartitioned into two or more blocks of a next lower level, e.g.,tree-level 2 (hierarchy-level 2, depth 2), etc. until the partitioningis terminated, e.g., because a termination criterion is fulfilled, e.g.,a maximum tree depth or minimum block size is reached. Blocks which arenot further partitioned are also referred to as leaf-blocks or leafnodes of the tree. A tree using partitioning into two partitions isreferred to as binary-tree (BT), a tree using partitioning into threepartitions is referred to as ternary-tree (TT), and a tree usingpartitioning into four partitions is referred to as quad-tree (QT).

As mentioned before, the term “block” as used herein may be a portion,in particular a square or rectangular portion, of a picture. Withreference, for example, to HEVC and VVC, the block may be or correspondto a coding tree unit (CTU), a coding unit (CU), prediction unit (PU),and transform unit (TU) and/or to the corresponding blocks, e.g., acoding tree block (CTB), a coding block (CB), a transform block (TB) orprediction block (PB).

For example, a coding tree unit (CTU) may be or comprise a CTB of lumasamples, two corresponding CTBs of chroma samples of a picture that hasthree sample arrays, or a CTB of samples of a monochrome picture or apicture that is coded using three separate color planes and syntaxstructures used to code the samples. Correspondingly, a coding treeblock (CTB) may be an N×N block of samples for some value of N such thatthe division of a component into CTBs is a partitioning. A coding unit(CU) may be or comprise a coding block of luma samples, twocorresponding coding blocks of chroma samples of a picture that hasthree sample arrays, or a coding block of samples of a monochromepicture or a picture that is coded using three separate color planes andsyntax structures used to code the samples. Correspondingly a codingblock (CB) may be an M×N block of samples for some values of M and Nsuch that the division of a CTB into coding blocks is a partitioning.

In embodiments, e.g., according to HEVC, a coding tree unit (CTU) may besplit into CUs by using a quad-tree structure denoted as coding tree.The decision whether to code a picture area using inter-picture(temporal) or intra-picture (spatial) prediction is made at the CUlevel. Each CU can be further split into one, two or four PUs accordingto the PU splitting type. Inside one PU, the same prediction process isapplied and the relevant information is transmitted to the decoder on aPU basis. After obtaining the residual block by applying the predictionprocess based on the PU splitting type, a CU can be partitioned intotransform units (TUs) according to another quadtree structure similar tothe coding tree for the CU.

In embodiments, e.g., according to the latest video coding standardcurrently in development, which is referred to as Versatile Video Coding(VVC), Quad-tree and binary tree (QTBT) partitioning is used topartition a coding block. In the QTBT block structure, a CU can haveeither a square or rectangular shape. For example, a coding tree unit(CTU) is first partitioned by a quadtree structure. The quadtree leafnodes are further partitioned by a binary tree or ternary (or triple)tree structure. The partitioning tree leaf nodes are called coding units(CUs), and that segmentation is used for prediction and transformprocessing without any further partitioning. This means that the CU, PUand TU have the same block size in the QTBT coding block structure. Inparallel, multiple partition, for example, triple tree partition wasalso proposed to be used together with the QTBT block structure.

In one example, the mode selection unit 260 of video encoder 20 may beconfigured to perform any combination of the partitioning techniquesdescribed herein.

As described above, the video encoder 20 is configured to determine orselect the best or an optimum prediction mode from a set of(pre-determined) prediction modes. The set of prediction modes maycomprise, e.g., intra-prediction modes and/or inter-prediction modes.

Intra-Prediction

The set of intra-prediction modes may comprise 35 differentintra-prediction modes, e.g., non-directional modes like DC (or mean)mode and planar mode, or directional modes, e.g., as defined in HEVC, ormay comprise 67 different intra-prediction modes, e.g., non-directionalmodes like DC (or mean) mode and planar mode, or directional modes,e.g., as defined for VVC.

The intra-prediction unit 254 is configured to use reconstructed samplesof neighboring blocks of the same current picture to generate anintra-prediction block 265 according to an intra-prediction mode of theset of intra-prediction modes.

The intra prediction unit 254 (or in general the mode selection unit260) is further configured to output intra-prediction parameters (or ingeneral information indicative of the selected intra prediction mode forthe block) to the entropy encoding unit 270 in form of syntax elements266 for inclusion into the encoded picture data 21, so that, e.g., thevideo decoder 30 may receive and use the prediction parameters fordecoding.

Inter-Prediction

The set of (or possible) inter-prediction modes depends on the availablereference pictures (e.g., previous at least partially decoded pictures,e.g., stored in DBP 230) and other inter-prediction parameters, e.g.,whether the whole reference picture or only a part, e.g., a searchwindow area around the area of the current block, of the referencepicture is used for searching for a best matching reference block,and/or e.g., whether pixel interpolation is applied, e.g., half/semi-peland/or quarter-pel interpolation, or not.

Additional to the above prediction modes, skip mode and/or direct modemay be applied.

The inter prediction unit 244 may include a motion estimation (ME) unitand a motion compensation (MC) unit (both not shown in FIG. 2 ). Themotion estimation unit may be configured to receive or obtain thepicture block 203 (current picture block 203 of the current picture 17)and a decoded picture 231, or at least one or a plurality of previouslyreconstructed blocks, e.g., reconstructed blocks of one or a pluralityof other/different previously decoded pictures 231, for motionestimation. E.g., a video sequence may comprise the current picture andthe previously decoded pictures 231, or in other words, the currentpicture and the previously decoded pictures 231 may be part of or form asequence of pictures forming a video sequence.

The encoder 20 may, e.g., be configured to select a reference block froma plurality of reference blocks of the same or different pictures of theplurality of other pictures and provide a reference picture (orreference picture index) and/or an offset (spatial offset) between theposition (x, y coordinates) of the reference block and the position ofthe current block as inter prediction parameters to the motionestimation unit. This offset is also called motion vector (MV).

The motion compensation unit is configured to obtain, e.g., receive, aninter prediction parameter and to perform inter prediction based on orusing the inter prediction parameter to obtain an inter prediction block265. Motion compensation, performed by the motion compensation unit, mayinvolve fetching or generating the prediction block based on themotion/block vector determined by motion estimation, possibly performinginterpolations to sub-pixel precision. Interpolation filtering maygenerate additional pixel samples from known pixel samples, thuspotentially increasing the number of candidate prediction blocks thatmay be used to code a picture block. Upon receiving the motion vectorfor the PU of the current picture block, the motion compensation unitmay locate the prediction block to which the motion vector points in oneof the reference picture lists.

Motion compensation unit may also generate syntax elements associatedwith the blocks and the video slice for use by video decoder 30 indecoding the picture blocks of the video slice.

Entropy Coding

The entropy encoding unit 270 is configured to apply, for example, anentropy encoding algorithm or scheme (e.g., a variable length coding(VLC) scheme, an context adaptive VLC scheme (CAVLC), an arithmeticcoding scheme, a binarization, a context adaptive binary arithmeticcoding (CABAC), syntax-based context-adaptive binary arithmetic coding(SBAC), probability interval partitioning entropy (PIPE) coding oranother entropy encoding methodology or technique) or bypass (nocompression) on the quantized coefficients 209, inter predictionparameters, intra prediction parameters, loop filter parameters and/orother syntax elements to obtain encoded picture data 21 which can beoutput via the output 272, e.g., in the form of an encoded bitstream 21,so that, e.g., the video decoder 30 may receive and use the parametersfor decoding. The encoded bitstream 21 may be transmitted to videodecoder 30, or stored in a memory for later transmission or retrieval byvideo decoder 30.

Other structural variations of the video encoder 20 can be used toencode the video stream. For example, a non-transform based encoder 20can quantize the residual signal directly without the transformprocessing unit 206 for certain blocks or frames. In anotherimplementation, an encoder 20 can have the quantization unit 208 and theinverse quantization unit 210 combined into a single unit.

Decoder and Decoding Method

FIG. 3 shows an example of a video decoder 30 that is configured toimplement the techniques of this present disclosure. The video decoder30 is configured to receive encoded picture data 21 (e.g., encodedbitstream 21), e.g., encoded by encoder 20, to obtain a decoded picture331. The encoded picture data or bitstream comprises information fordecoding the encoded picture data, e.g., data that represents pictureblocks of an encoded video slice and associated syntax elements.

In the example of FIG. 3 , the decoder 30 comprises an entropy decodingunit 304, an inverse quantization unit 310, an inverse transformprocessing unit 312, a reconstruction unit 314 (e.g., a summer 314), aloop filter 320, a decoded picture buffer (DBP) 330, an inter predictionunit 344 and an intra prediction unit 354. Inter prediction unit 344 maybe or include a motion compensation unit. Video decoder 30 may, in someexamples, perform a decoding pass generally reciprocal to the encodingpass described with respect to video encoder 100 from FIG. 2 .

As explained with regard to the encoder 20, the inverse quantizationunit 210, the inverse transform processing unit 212, the reconstructionunit 214 the loop filter 220, the decoded picture buffer (DPB) 230, theinter prediction unit 344 and the intra prediction unit 354 are alsoreferred to as forming the “built-in decoder” of video encoder 20.Accordingly, the inverse quantization unit 310 may be identical infunction to the inverse quantization unit 110, the inverse transformprocessing unit 312 may be identical in function to the inversetransform processing unit 212, the reconstruction unit 314 may beidentical in function to reconstruction unit 214, the loop filter 320may be identical in function to the loop filter 220, and the decodedpicture buffer 330 may be identical in function to the decoded picturebuffer 230. Therefore, the explanations provided for the respectiveunits and functions of the video encoder apply correspondingly to therespective units and functions of the video decoder 30.

Entropy Decoding

The entropy decoding unit 304 is configured to parse the bitstream 21(or in general encoded picture data 21) and perform, for example,entropy decoding to the encoded picture data 21 to obtain, e.g.,quantized coefficients 309 and/or decoded coding parameters (not shownin FIG. 3 ), e.g., any or all of inter prediction parameters (e.g.,reference picture index and motion vector), intra prediction parameter(e.g., intra prediction mode or index), transform parameters,quantization parameters, loop filter parameters, and/or other syntaxelements. Entropy decoding unit 304 maybe configured to apply thedecoding algorithms or schemes corresponding to the encoding schemes asdescribed with regard to the entropy encoding unit 270 of the encoder20. Entropy decoding unit 304 may be further configured to provide interprediction parameters, intra prediction parameter and/or other syntaxelements to the mode selection unit 360 and other parameters to otherunits of the decoder 30. Video decoder 30 may receive the syntaxelements at the video slice level and/or the video block level.

Inverse Quantization

The inverse quantization unit 310 may be configured to receivequantization parameters (QP) (or in general information related to theinverse quantization) and quantized coefficients from the encodedpicture data 21 (e.g., by parsing and/or decoding, e.g., by entropydecoding unit 304) and to apply based on the quantization parameters aninverse quantization on the decoded quantized coefficients 309 to obtaindequantized coefficients 311, which may also be referred to as transformcoefficients 311. The inverse quantization process may include use of aquantization parameter determined by video encoder 20 for each videoblock in the video slice to determine a degree of quantization and,likewise, a degree of inverse quantization that should be applied.

Inverse Transform

Inverse transform processing unit 312 may be configured to receivedequantized coefficients 311, also referred to as transform coefficients311, and to apply a transform to the dequantized coefficients 311 inorder to obtain reconstructed residual blocks 213 in the sample domain.The reconstructed residual blocks 213 may also be referred to astransform blocks 313. The transform may be an inverse transform, e.g.,an inverse DCT, an inverse DST, an inverse integer transform, or aconceptually similar inverse transform process. The inverse transformprocessing unit 312 may be further configured to receive transformparameters or corresponding information from the encoded picture data 21(e.g., by parsing and/or decoding, e.g., by entropy decoding unit 304)to determine the transform to be applied to the dequantized coefficients311.

Reconstruction

The reconstruction unit 314 (e.g., adder or summer 314) may beconfigured to add the reconstructed residual block 313, to theprediction block 365 to obtain a reconstructed block 315 in the sampledomain, e.g., by adding the sample values of the reconstructed residualblock 313 and the sample values of the prediction block 365.

Filtering

The loop filter unit 320 (either in the coding loop or after the codingloop) is configured to filter the reconstructed block 315 to obtain afiltered block 321, e.g., to smooth pixel transitions, or otherwiseimprove the video quality. The loop filter unit 320 may comprise one ormore loop filters such as a de-blocking filter, a sample-adaptive offset(SAO) filter or one or more other filters, e.g., a bilateral filter, anadaptive loop filter (ALF), a sharpening, a smoothing filters or acollaborative filters, or any combination thereof. Although the loopfilter unit 320 is shown in FIG. 3 as being an in loop filter, in otherconfigurations, the loop filter unit 320 may be implemented as a postloop filter.

Decoded Picture Buffer

The decoded video blocks 321 of a picture are then stored in decodedpicture buffer 330, which stores the decoded pictures 331 as referencepictures for subsequent motion compensation for other pictures and/orfor output respectively display.

The decoder 30 is configured to output the decoded picture 311, e.g.,via output 312, for presentation or viewing to a user.

Prediction

The inter prediction unit 344 may be identical to the inter predictionunit 244 (in particular to the motion compensation unit) and the intraprediction unit 354 may be identical to the inter prediction unit 254 infunction, and performs split or partitioning decisions and predictionbased on the partitioning and/or prediction parameters or respectiveinformation received from the encoded picture data 21 (e.g., by parsingand/or decoding, e.g., by entropy decoding unit 304). Mode selectionunit 360 may be configured to perform the prediction (intra or interprediction) per block based on reconstructed pictures, blocks orrespective samples (filtered or unfiltered) to obtain the predictionblock 365.

When the video slice is coded as an intra coded (I) slice, intraprediction unit 354 of mode selection unit 360 is configured to generateprediction block 365 for a picture block of the current video slicebased on a signaled intra prediction mode and data from previouslydecoded blocks of the current picture. When the video picture is codedas an inter coded (e.g., B, or P) slice, inter prediction unit 344(e.g., motion compensation unit) of mode selection unit 360 isconfigured to produce prediction blocks 365 for a video block of thecurrent video slice based on the motion vectors and other syntaxelements received from entropy decoding unit 304. For inter prediction,the prediction blocks may be produced from one of the reference pictureswithin one of the reference picture lists. Video decoder 30 mayconstruct the reference frame lists, List 0 and List 1, using defaultconstruction techniques based on reference pictures stored in DPB 330.

Mode selection unit 360 is configured to determine the predictioninformation for a video block of the current video slice by parsing themotion vectors and other syntax elements, and uses the predictioninformation to produce the prediction blocks for the current video blockbeing decoded. For example, the mode selection unit 360 uses some of thereceived syntax elements to determine a prediction mode (e.g., intra orinter prediction) used to code the video blocks of the video slice, aninter prediction slice type (e.g., B slice, P slice, or GPB slice),construction information for one or more of the reference picture listsfor the slice, motion vectors for each inter encoded video block of theslice, inter prediction status for each inter coded video block of theslice, and other information to decode the video blocks in the currentvideo slice.

Other variations of the video decoder 30 can be used to decode theencoded picture data 21. For example, the decoder 30 can produce theoutput video stream without the loop filtering unit 320. For example, anon-transform based decoder 30 can inverse-quantize the residual signaldirectly without the inverse-transform processing unit 312 for certainblocks or frames. In another implementation, the video decoder 30 canhave the inverse-quantization unit 310 and the inverse-transformprocessing unit 312 combined into a single unit.

It should be understood that, in the encoder 20 and the decoder 30, aprocessing result of a current operation may be further processed andthen output to the next operation. For example, after interpolationfiltering, motion vector derivation or loop filtering, a furtheroperation, such as Clip or shift, may be performed on the processingresult of the interpolation filtering, motion vector derivation or loopfiltering.

It should be noted that further operations may be applied to the derivedmotion vectors of current block (including but not limit to controlpoint motion vectors of affine mode, sub-block motion vectors in affine,planar, ATMVP modes, temporal motion vectors, and so on). For example,the value of motion vector is constrained to a predefined rangeaccording to its representing bit. If the representing bit of motionvector is bitDepth, then the range is −2{circumflex over( )}(bitDepth−1)˜2{circumflex over ( )}(bitDepth−1)−1, where“{circumflex over ( )}” means exponentiation. For example, if bitDepthis set equal to 16, the range is −32768˜32767; if bitDepth is set equalto 18, the range is −13107˜2131071. For example, the value of thederived motion vector (e.g., the MVs of four 4×4 sub-blocks within one8×8 block) is constrained such that the max difference between integerparts of the four 4×4 sub-block MVs is no more than N pixels, such as nomore than 1 pixel.

The following refers to two methods for constraining the motion vectoraccording to the bitDepth.

Method 1: remove the overflow MSB (most significant bit) by flowingoperationsux=(mvx±2^(bitDepth))%2^(bitDepth)  (1)mvx=(ux>=2^(bitDepth-1))?(ux−2^(bitDepth))  (2)uy=(mvy+2^(bitDepth))%2^(bitDepth)  (3)mvy=(uy{circumflex over ( )}−2^(bitDepth-1))?(uy−2^(bitDepth)):uy  (4)where mvx is a horizontal component of a motion vector of an image blockor a sub-block, mvy is a vertical component of a motion vector of animage block or a sub-block, and ux and uy indicates an intermediatevalue;

For example, if the value of mvx is −32769, after applying formula (1)and (2), the resulting value is 32767. In computer system, decimalnumbers are stored as two's complement. The two's complement of −32769is 1,0111,1111,1111,1111 (17 bits), then the MSB is discarded, so theresulting two's complement is 0111,1111,1111,1111 (decimal number is32767), which is same as the output by applying formula (1) and (2).ux=(mvpx+mvdx+2^(bitDepth))%2^(bitDepth)  (5)mvx=(ux>=2^(bitDepth-1))?(ux−2^(bitDepth))  (6)uy=(mvpy+mvdy+2^(bitDepth))%2^(bitDepth)  (7)mvy=(uy>=2^(bitDepth-1))?(uy−2^(bitDepth)):uy  (8)

The operations may be applied during the sum of mvp and mvd, as shown informula (5) to (8).

Method 2: remove the overflow MSB by clipping the valuevx=Clip3(−2^(bitDepth-1),2^(bitDepth-1)−1,vx)vy=Clip3(−2^(bitDepth-1),2^(bitDepth-1)−1,vy)

-   -   where vx is a horizontal component of a motion vector of an        image block or a sub-block, vy is a vertical component of a        motion vector of an image block or a sub-block; x, y and z        respectively correspond to three input value of the MV clipping        process, and the definition of function Clip3 is as follow:

${{Clip}3\left( {x,y,z} \right)} = \left\{ \begin{matrix}x & ; & {z < x} \\y & ; & {x > y} \\z & ; & {otherwise}\end{matrix} \right.$

FIG. 4 is a schematic diagram of a video coding device 400 according toan embodiment of the disclosure. The video coding device 400 is suitablefor implementing the disclosed embodiments as described herein. In anembodiment, the video coding device 400 may be a decoder such as videodecoder 30 of FIG. 1A or an encoder such as video encoder of FIG. 1A.

The video coding device 400 comprises ingress ports 410 (or input ports410) and receiver units (Rx) 420 for receiving data; a processor, logicunit, or central processing unit (CPU) 430 to process the data;transmitter units (Tx) 440 and egress ports 450 (or output ports 450)for transmitting the data; and a memory 460 for storing the data. Thevideo coding device 400 may also comprise optical-to-electrical (OE)components and electrical-to-optical (EO) components coupled to theingress ports 410, the receiver units 420, the transmitter units 440,and the egress ports 450 for egress or ingress of optical or electricalsignals.

The processor 430 is implemented by hardware and software. The processor430 may be implemented as one or more CPU chips, cores (e.g., as amulti-core processor), FPGAs, ASICs, and DSPs. The processor 430 is incommunication with the ingress ports 410, receiver units 420,transmitter units 440, egress ports 450, and memory 460. The processor430 comprises a coding module 470. The coding module 470 implements thedisclosed embodiments described above. For instance, the coding module470 implements, processes, prepares, or provides the various codingoperations. The inclusion of the coding module 470 therefore provides asubstantial improvement to the functionality of the video coding device400 and effects a transformation of the video coding device 400 to adifferent state. Alternatively, the coding module 470 is implemented asinstructions stored in the memory 460 and executed by the processor 430.

The memory 460 may comprise one or more disks, tape drives, andsolid-state drives and may be used as an over-flow data storage device,to store programs when such programs are selected for execution, and tostore instructions and data that are read during program execution. Thememory 460 may be, for example, volatile and/or non-volatile and may bea read-only memory (ROM), random access memory (RAM), ternarycontent-addressable memory (TCAM), and/or static random-access memory(SRAM).

FIG. 5 is a simplified block diagram of an apparatus 500 that may beused as either or both of the source device 12 and the destinationdevice 14 from FIG. 1 according to an exemplary embodiment.

A processor 502 in the apparatus 500 can be a central processing unit.Alternatively, the processor 502 can be any other type of device, ormultiple devices, capable of manipulating or processing informationnow-existing or hereafter developed. Although the disclosedimplementations can be practiced with a single processor as shown, e.g.,the processor 502, advantages in speed and efficiency can be achievedusing more than one processor.

A memory 504 in the apparatus 500 can be a read only memory (ROM) deviceor a random access memory (RAM) device in an implementation. Any othersuitable type of storage device can be used as the memory 504. Thememory 504 can include code and data 506 that is accessed by theprocessor 502 using a bus 512. The memory 504 can further include anoperating system 508 and application programs 510, the applicationprograms 510 including at least one program that permits the processor502 to perform the methods described here. For example, the applicationprograms 510 can include applications 1 through N, which further includea video coding application that performs the methods described here.

The apparatus 500 can also include one or more output devices, such as adisplay 518. The display 518 may be, in one example, a touch sensitivedisplay that combines a display with a touch sensitive element that isoperable to sense touch inputs. The display 518 can be coupled to theprocessor 502 via the bus 512.

Although depicted here as a single bus, the bus 512 of the apparatus 500can be composed of multiple buses. Further, the secondary storage 514can be directly coupled to the other components of the apparatus 500 orcan be accessed via a network and can comprise a single integrated unitsuch as a memory card or multiple units such as multiple memory cards.The apparatus 500 can thus be implemented in a wide variety ofconfigurations.

Intra Prediction Modes

According to the HEVC/H.265 standard, 35 intra prediction modes areavailable. As shown in FIG. 6 , this set contains the following modes:planar mode (the intra prediction mode index is 0), DC mode (the intraprediction mode index is 1), and directional (angular) modes that coverthe 180° range and have the intra prediction mode index value range of 2to 34 shown by black arrows in FIG. 6 . To capture the arbitrary edgedirections present in natural video, the number of directional intramodes is extended from 33, as used in HEVC, to 65. The additionaldirectional modes are depicted as dotted arrows in FIG. 6 , and theplanar and DC modes remain the same. It is worth noting that the rangethat is covered by intra prediction modes can be wider than 180°. Inparticular, 62 directional modes with index values of 3 to 64 cover therange of approximately 230°, e.g., several pairs of modes have oppositedirectionality. In the case of the HEVC Reference Model (HM) and JEMplatforms, only one pair of angular modes (namely, modes 2 and 66) hasopposite directionality as shown in FIG. 6 . For constructing apredictor, conventional angular modes take reference samples and (ifneeded) filter them to get a sample predictor. The number of referencesamples required for constructing a predictor depends on the length ofthe filter used for interpolation (e.g., bilinear and cubic filters havelengths of 2 and 4, respectively).

FIG. 4 shows an example of 67 intra prediction modes, e.g., as proposedfor VVC, the plurality of intra prediction modes of 67 intra predictionmodes comprising: planar mode (index 0), dc mode (index 1), and angularmodes with indices 2 to 66, wherein the left bottom angular mode in FIG.6 refers to index 2 and the numbering of the indices being incrementeduntil index 66 being the top right most angular mode of FIG. 6 .

Most Probable Mode List Construction

Most Probable Mode (MPM) list is used in intra mode coding to improvecoding efficiency. Due to the large number of intra modes (e.g., 35 inITU H.265 and 67 in VVC), a Most Probable Mode list of current CU(coding unit) or CB (coding block) is constructed based on itsneighboring CUs' or CBs' intra prediction modes. As current CU's or CB'sintra mode is relevant to its neighbors CUs' or CBs' intra predictionmodes, the MPM list usually provides a good prediction, s the intra modeof current CU or CB has a high chance falling into the MPM list. In thisway, to derive the intra mode of current CU or CB, the index of MPM listis signaled. Compared to the number of total intra modes, the length ofMPM list is much smaller (e.g., 3-MPM list is used in HEVC and 6-MPMlist is used in VVC), thus less bits are required to code the intramode. A flag (for example, mpm_flag) is used to indicate whether currentCU's or CB's intra mode is in the MPM list or not. If the value of theflag is true (for example, the value is 1), the intra mode of current CUor CB is in the MPM list. If the value of the flag is false (forexample, the value is 0), the intra mode of current CU or CB is not inthe MPM list and the intra mode of current CU or CB is signaled using abinarized code.

MPM List Construction in VVC and ITU H.265

In VVC and ITU H.265, a MPM list is constructed based on the neighboringleft and top blocks of the current block. When the left block and topblock of the current block are unavailable for intra prediction, a modelist is used.

In one example for a 6-MPM list construction, a mode list might includethe following intra prediction modes in order: (1) planar mode, (2) DCmode, (3) Vertical Mode, (4) Horizontal Mode, (5) V−4 mode (e.g., intramode 46), (6) V+4 mode (e.g., intra mode 54). In another example for a3-MPM list construction, a default mode list might include the followingintra prediction modes in order: (1) planar mode, (2) DC mode.

Binarization of the Index of the Current Block when an Intra Mode of theCurrent Block is in the MPM List.

Binarization is used to convert decimal to binary representation. Manybinarization approaches are used in ITU-T H.265 and VVC, such as fixedlength code, truncated unary code, and truncated binary code. Truncatedunary code is used to code an index corresponding to a 6-MPM list.Truncated unary binarization represents the mpm idx (suppose it is n,the value of n is ranged between 0 to 5, inclusive) with n 1 followed by0, except the maximum value where all n bits are 1, or alternatively,with n 0 followed by 1, except the maximum value where all n bits are 0.The binarization code of mpm index with a maximum value of 5 is shown inTable 1,

TABLE 1 Binary Binary Decimal representation representation valuealternative 1 alternative 2 0 0 1 1 10 01 2 110 001 3 1110 0001 4 1111000001 5 11111 00000

In the above examples, each decimal value is coded according to one morebit in the binary representation compared to the preceding decimal value(decimal value which is one less), except for the last decimal valuewhich corresponds to the maximum value of the index.

Multi-Hypothesis Prediction

A coding block is either intra-predicted (e.g., using the referencesamples in the same picture) or inter-predicted (e.g., using thereference samples in other pictures). The multi-hypothesis predictioncombines these two prediction approaches. Therefore, it is sometimesalso called as combined inter-intra prediction. When combinedinter-intra prediction is enabled, the intra-predicted andinter-predicted samples are applied by weights, and the final predictionfor a coding block is derived as the weighted average samples.

In VTM 3.0, if multi-hypothesis (MH) prediction is enabled, 4 or 3 intramodes based on block shape is used. In 4 intra modes case, PLANAR, DC,vertical (corresponding to value 50), and horizontal modes(corresponding to 18) are used. In 3 intra modes case, when the CU or CBwidth is larger than the double of CU or CB height, horizontal mode isexclusive of the intra mode list; when the CU or CB height is largerthan the double of CU or CB width, vertical mode is removed from theintra mode list. For both cases of 3 and 4 intra modes, only these fourintra modes (e.g., PLANAR, DC, vertical, and horizontal) are allowed anda 3-MPM list is defined.

MEI Blocks: The Coding Blocks of the Luma Component that are Predictedby Multi-Hypothesis Prediction.

Intra blocks: The coding blocks that are predicted by intra predictionbut not predicted by multi-hypothesis prediction. The MPM listconstruction for MH blocks is different from the MPM list constructionfor intra blocks in VTM3.0. In an example, a 6-MPM list is constructedand 67 intra modes may be used for intra prediction. The MPM listconstruction for intra blocks is constructed based on the left block'sand above block's intra prediction modes, if the left block's intraprediction mode and the above block's intra prediction mode are notavailable, a six-entry default mode list {PLANAR, DC, vertical,horizontal, vertical−4, vertical+4} may be used.

In another aspect, the binarization for a mpm list index of MH blocks isdifferent from the binarization for a mpm list index of an intra blocks.First, for MH blocks, a 3-MPM list is defined and the maximum value ofmpm list index is 2, while for intra blocks, a 6-MPM list is defined andthe maximum value of mpm list index is 5. Second, in 3 or 4 intra modecases the index binarization for MH blocks is combined with thesignaling of mpm_flag. When in the 3 intra mode case, mpm_flag is notsignaled but inferred as true, since the intra mode should fall into the3-MPM list after excluding horizontal or vertical modes. When in the 4intra mode case, mpm_flag is signaled, if the value of the mpm_flag true(for example, the value of the mpm_flag is 1), mpm_idx is coded withtruncated unary code, maximum value of the truncated unary code is 2; ifthe value of the mpm_flag is false (for example, the value of thempm_flag is 0), the intra mode is obtained by excluding the 3 intramodes in the 3-MPM list from the 4 modes {PLANAR, DC, vertical, andhorizontal}.

The binarization of MPM list index of MH blocks, as well as mpm_flagsignaling for 3 and 4 intra mode cases are represented by Table 2.

TABLE 2 Mpm index 3 intra mode case 4 intra mode case 0  0  0 1 10 10 211 11 Mpm flag 0 — Excluding 3 MPM modes (not exist, always 1) from{PLANAR, DC, vertical, and horizontal} 1 use index to indicate intra useindex to indicate intra mode in the 3-MPM list mode in the 3-MPM list

The block-based approach in VTM differentiating 3 or 4 MPM for MH blocksincreases the decoding complexity, and might not be necessary for blocksapplied with multi-hypothesis prediction (e.g., combined inter-intraprediction).

Embodiment of the present disclosure provides several alternatives forreducing the complexity of decoding a block of a picture through MHprediction, especially benefited from the simplifications of the MPMlist construction for MH blocks.

Embodiment 1

Determining whether multi-hypothesis prediction is applied to a codingblock or not;

-   -   If multi-hypothesis prediction is applied to predict the coding        block,        -   Using a first MPM list with a pre-defined default list of            modes for intra prediction, which has a size of N (N is            larger than 0).        -   Predicting the block based on one of the entries of the            first MPM list.    -   If multi-hypothesis prediction is not applied to predict the        coding block, and if intra prediction is applied to predict the        block,        -   Predicting the block based on one of the entries of a second            MPM list (in an example, the second MPM list is constructed            according to the method which is disclosed in JVET-L1001).

In one implementation, the default mode list has a length of 4, and thelist is comprised of following entries with the specified order, Planarmode, DC mode, vertical mode, and horizontal mode.

In one implementation, the default mode list has a length of 3, and thelist is comprised of following entries with the specified order, Planarmode, DC mode, vertical mode.

In one implementation, the default mode list has a length of 2, and thelist is comprised of following entries with the specified order, Planarmode, DC mode.

In one implementation, the default mode list has a length of 1, and thelist is comprised of Planar mode only.

In one implementation, the binarization of mpm list index uses truncatedunary code, the maximum value of the truncated unary code is 3, when afirst MPM list has 4 intra modes, and the mpm_flag is always set to true(the value of the mpm_flag is 1).

In another implementation, the first 4 candidates in the default modelist are used to construct a first MPM list that has four intra modes.The order of the 4 candidates in the default mode list are same as theorder of the candidates in the first MPM list. As an example if thedefault mode list comprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the first MPM list comprises the following intra prediction        modes in order:        -   1. planar mode,        -   2. DC mode,        -   3. Vertical Mode,        -   4. Horizontal Mode.

In one implementation, the first 3 candidates in the default mode listare used to construct a first MPM list that has 3 intra modes.

In one implementation, the binarization of mpm list index uses truncatedunary code, the maximum value of the truncated unary code is 2, when afirst MPM list has 3 intra modes, and the mpm_flag is always set to true(the value of the mpm_flag is 1).

In another implementation, the first 3 candidates in the default modelist are used to construct a first MPM list that has 3 intra modes. Theorder of the 3 candidates in the default mode list are same as the orderof the candidates in the first MPM list. As an example, if the defaultmode list comprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the first MPM list comprises the following intra prediction        modes in order:        -   1. planar mode,        -   2. DC mode,        -   3. Vertical Mode

In one implementation, the first 2 candidates in the default mode listare used to construct a first MPM list that has 2 intra modes.

In one implementation, the binarization of mpm list index uses truncatedunary code with a maximum value of 1, when a first MPM list has 2 intramodes, and the mpm_flag is always set to true (the value of the mpm_flagis 1).

In another implementation, the first 2 candidates in the default modelist are used to construct a first MPM list that has 2 intra modes. Theorder of the 2 candidates in the default mode list are same as the orderof the candidates in the first MPM list. As an example, if the defaultmode list comprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the first MPM list comprises the following intra prediction        modes in order:        -   1. planar mode,        -   2. DC mode,

In one implementation, the first one candidate in the default mode listis used to construct a first MPM list that has one intra mode. In oneexample, the mode that is inserted in the first MPM list is Planar mode.

In one implementation, mpm_idx is not signaled if a first MPM list hasone intra mode and is coded with a fixed intra mode, and the mpm_flag isalways set to true (the value of the mpm_flag is 1).

In another implementation, the first candidate in the default mode listis used to construct a first MPM list that has one intra mode. As anexample, if the default mode list comprises the following intraprediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the first MPM list comprises the following intra prediction        modes in order:        -   1. planar mode,

The second MPM list could be constructed according to the methods in theITU-T H.265 and in the VVC, see the above examples and disclosures aboutthe MPM list construction process in ITU-T H.265 and in VVC.

Embodiment 2

Constructing a first MPM list (in an example, the first MPM list isconstructed according to the method which is disclosed in JVET-L1001)

Determining whether multi-hypothesis prediction is applied to a codingblock or not;

-   -   If multi-hypothesis prediction is applied to predict the coding        block,        -   Predicting the block based on one of the entries in the            first MPM list.    -   If multi-hypothesis prediction is not applied to predict the        coding block, and if intra prediction is applied to predict the        block,        -   Predicting the block based on one of the entries of the            first MPM list.

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: construct all of the entries of the first MPM list    -   Operation 2: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 3:        -   multi-hypothesis prediction is applied to predict the coding            block            -   Parse an index indication from a bitstream, whose                maximum value is known as (N−1), N is equal to or larger                than 1. When N is 1, the index indication is inferred                (but not parsed) as 0.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication            -   if the derived intra prediction mode is an angular mode                with mode index (a corresponding value of intra mode)                between 2 and 34, inclusive, the derived intra                prediction is changed to a horizontal mode            -   otherwise if the derived intra prediction is an angular                mode with mode index between 35 and 66, inclusive, the                derived intra prediction is changed to a vertical mode        -   If multi-hypothesis prediction is not applied to predict the            block and if the block is applied with intra prediction            -   Parse an index indication from a bitstream, whose                maximum value is known as (M−1), M is equal to or larger                than 1.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication    -   Operation 4: Predicting the block based on the derived intra        mode.

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: construct all of the entries of the first MPM list    -   Operation 2: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 3:        -   If multi-hypothesis prediction is applied to predict the            coding block            -   Parse an index indication from a bitstream, whose                maximum value is known as (N−1), N is equal to or larger                than 1. When N is 1, the index indication is inferred                (but not parsed) as 0.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication            -   if the derived intra prediction mode is an angular mode                with mode index (a corresponding value of intra mode)                between 2 and 33, inclusive, the derived intra                prediction is changed to a horizontal mode            -   otherwise if the derived intra prediction is an angular                mode with mode index between 34 and 66, inclusive, the                derived intra prediction is changed to a vertical mode        -   If multi-hypothesis prediction is not applied to predict the            block and if the block is applied with intra prediction            -   Parse an index indication from a bitstream, whose                maximum value is known as (M−1), M is equal to or larger                than 1.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication    -   Operation 4: Predicting the block based on the derived intra        mode

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: construct all of the entries of the first MPM list    -   Operation 2: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 3:        -   If multi-hypothesis prediction is applied to predict the            coding block            -   Parse an index indication from a bitstream, whose                maximum value is known as (N−1), N is equal to or larger                than 1. When N is 1, the index indication is inferred                (but not parsed) as 0.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication            -   if the derived intra prediction mode is an angular mode                with mode index (a corresponding value of intra mode)                between 2 and 66, inclusive, the derived intra                prediction is changed to a Planar mode            -   Predicting the block based on the derived intra mode.        -   If multi-hypothesis prediction is not applied to predict the            block and if the block is applied with intra prediction            -   Parse an index indication from a bitstream, whose                maximum value is known as (M−1), M is equal to or larger                than 1.            -   Derive an intra prediction mode according to the first                MPM list and the derived index indication. The derived                intra prediction mode is the entry in the first MPM list                indexed by the index indication    -   Operation 4: Predicting the block based on the derived intra        mode.

Embodiment 3

Determining whether a block applies multi-hypothesis prediction or not;

-   -   If multi-hypothesis prediction is applied to predict the block,        -   Constructing the first N entries of a first MPM list (in an            example, the first MPM list is constructed according to the            method which is disclosed in JVET-L1001).        -   Predicting the block based on one of the entries of the            first MPM list.    -   If multi-hypothesis prediction is not applied to predict the        block and if the block is applied with intra prediction        -   Constructing all of the entries of a first MPM list (in an            example, the first MPM list is constructed according to the            method which is disclosed in JVET-L1001).        -   Predicting the block based on one of the entries of the            first MPM list.

In one implementation, the first MPM list comprises only Planar, DC,Vertical and Horizontal intra prediction modes.

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 2:    -   If multi-hypothesis prediction is applied to predict the coding        block        -   construct first N entries of the first MPM list, namely,            construct first N entries of the first MPM list according to            the constructing rule of the first MPM list. When the first            N entries can be determined, stop constructing other entries            of the first MPM list.        -   Parse an index indication from a bitstream, whose maximum            value is known as (N−1), N is equal to or larger than 1.            When N is 1, the index indication is inferred (but not            parsed) as 0.        -   Derive an intra prediction mode according to first N entries            of the first MPM list and the derived index indication. The            derived intra prediction mode is the entry of the first N            entries of in the first MPM list indexed by the index            indication        -   if the derived intra prediction mode is an angular mode with            mode index (a corresponding value of intra mode) between 2            and 33, inclusive, the derived intra prediction is changed            to a horizontal mode (corresponds to a value 18)        -   otherwise if the derived intra prediction is an angular mode            with mode index between 34 and 66, inclusive, the derived            intra prediction is changed to a vertical mode (corresponds            to a value 50)    -   If multi-hypothesis prediction is not applied to predict the        block and if the block is applied with intra prediction        -   construct all M entries of the first MPM list.        -   Parse an index indication from a bitstream, whose maximum            value is known as (M−1), M is equal to or larger than 1.        -   Derive an intra prediction mode according to the first MPM            list and the derived index indication. The derived intra            prediction mode is the entry in the first MPM list indexed            by the index indication    -   Operation 3: Predicting the block based on the derived intra        mode.

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 2:    -   If multi-hypothesis prediction is applied to predict the coding        block        -   construct first N entries of the first MPM list, namely,            construct first N entries of the first MPM list according to            the constructing rule of the first MPM list. When the first            N entries can be determined, stop constructing other entries            of the first MPM list        -   Parse an index indication from a bitstream, whose maximum            value is known as (N−1), N is equal to or larger than 1.            When N is 1, the index indication is inferred (but not            parsed) as 0.        -   Derive an intra prediction mode according to first N entries            of the first MPM list and the derived index indication. The            derived intra prediction mode is the entry of the first N            entries of in the first MPM list indexed by the index            indication        -   if the derived intra prediction mode is an angular mode with            mode index (a corresponding value of intra mode) between 2            and 34, inclusive, the derived intra prediction is changed            to a horizontal mode (corresponds to a value 18)        -   otherwise if the derived intra prediction is an angular mode            with mode index between 35 and 66, inclusive, the derived            intra prediction is changed to a vertical mode (corresponds            to a value 50)    -   If multi-hypothesis prediction is not applied to predict the        block and if the block is applied with intra prediction        -   construct all M entries of the first MPM list        -   Parse an index indication from a bitstream, whose maximum            value is known as (M−1), M is equal to or larger than 1.        -   Derive an intra prediction mode according to the first MPM            list and the derived index indication. The derived intra            prediction mode is the entry in the first MPM list indexed            by the index indication    -   Operation 3: Predicting the block based on the derived intra        mode.

In one implementation the intra prediction based on one of the entriesin a first MPM list is performed as follows:

-   -   Operation 1: determine whether a block applies multi-hypothesis        prediction or not    -   Operation 2:    -   If multi-hypothesis prediction is applied to predict the coding        block        -   construct first N entries of the first MPM list, namely,            construct first N entries of the first MPM list according to            the constructing rule of the first MPM list. When the first            N entries can be determined, stop constructing other entries            of the first MPM list        -   Parse an index indication from a bitstream, whose maximum            value is known as (N−1), N is equal to or larger than 1.            When N is 1, the index indication is inferred (but not            parsed) as 0.        -   Derive an intra prediction mode according to first N entries            of the first MPM list and the derived index indication. The            derived intra prediction mode is the entry of the first N            entries of in the first MPM list indexed by the index            indication        -   if the derived intra prediction mode is an angular mode with            mode index (a corresponding value of intra mode) between 2            and 66, inclusive, the derived intra prediction is changed            to a Planar mode (corresponds to a value 0)    -   If multi-hypothesis prediction is not applied to predict the        block and if the block is applied with intra prediction        -   construct all M entries of the first MPM list        -   Parse an index indication from a bitstream, whose maximum            value is known as (M−1), M is equal to or larger than 1.        -   Derive an intra prediction mode according to the first MPM            list and the derived index indication. The derived intra            prediction mode is the entry in the first MPM list indexed            by the index indication    -   Operation 3: Predicting the block based on the derived intra        mode.

In one implementation the first MPM list is constructed based on thefirst N entries of the second MPM list as follows:

-   -   Operation 1: go to the first entry of the second MPM list    -   Operation 2.1: if the entry is Planar mode or DC mode, insert        the entry in the first MPM list.    -   Operation 2.2: otherwise if the entry is an angular mode with        mode index between 2 and 33, inclusive, insert a horizontal mode        in the first MPM list.    -   Operation 2.3: otherwise if the entry is an angular mode with        mode index between 34 and 66, inclusive, insert a vertical mode        in the first MPM list.    -   Operation 3: go to the next entry in the second MPM list restart        with operation 2.1 until the number of entries in the first MPM        list is equal to a specified maximum value.

In one implementation the first MPM list is constructed based on thefirst N entries of the second MPM list as follows:

-   -   Operation 1: go to the first entry of the second MPM list    -   Operation 2.1: if the entry is Planar mode or DC mode, insert        the entry in the first MPM list.    -   Operation 2.2: otherwise if the entry is an angular mode with        mode index between 2 and 34, inclusive, and if the horizontal        mode has not been inserted, insert a horizontal mode in the        first MPM list.    -   Operation 2.3: otherwise if the entry is an angular mode with        mode index between 35 and 66, inclusive, and if the vertical        mode has not been inserted, insert a vertical mode in the first        MPM list.    -   Operation 3: go to the next entry in the second MPM list restart        with operation 2.1 until the number of entries in the first MPM        list is equal to a specified maximum value or the first N        entries of the second MPM list have been all iterated.    -   Operation 4: fill one or more default modes that have not been        inserted into the first MPM list.

In one implementation the first MPM list is constructed based on thefirst N entries of the second MPM list as follows:

-   -   Operation 1: go to the first entry of the second MPM list    -   Operation 2.1: if the entry is Planar mode or DC mode, insert        the entry in the first MPM list.    -   Operation 2.2: otherwise if the entry is an angular mode with        mode index between 2 and 33, inclusive, and if the horizontal        mode has not been inserted, insert a horizontal mode in the        first MPM list.    -   Operation 2.3: otherwise if the entry is an angular mode with        mode index between 34 and 66, inclusive, and if the vertical        mode has not been inserted, insert a vertical mode in the first        MPM list.    -   Operation 3: go to the next entry in the second MPM list restart        with operation 2.1 until the number of entries in the first MPM        list is equal to a specified maximum value or the first N        entries of the second MPM list have been all iterated.    -   Operation 4: fill one or more default modes that have not been        inserted into the first MPM list.

In one implementation the first MPM list is constructed based on thefirst N entries of the second MPM list as follows:

-   -   Operation 1: go to the first entry of the second MPM list    -   Operation 2.1: if the entry is Planar mode or DC mode, insert        the entry in the first MPM list.    -   Operation 2.2: otherwise if the entry is an angular mode with        mode index between 2 and 66, inclusive, and if a default mode        has not been inserted, insert a default mode in the first MPM        list.    -   Operation 3: go to the next entry in the second MPM list restart        with operation 2.1 and fill with different default modes until        the number of entries in the first MPM list is equal to a        specified maximum value.

Embodiment 4

Determining whether multi-hypothesis prediction is applied to a codingblock or not;

-   -   If multi-hypothesis prediction is applied to predict the coding        block,        -   Using a first MPM list with a pre-defined default list (for            example, a default_list[N]) of modes for intra prediction,            which has a size of N (N is larger than 0).        -   Set mpm_flag as true, e.g., the mpm_flag is inferred as 1.            mpm_flag indicates whether the current block's intra mode is            in the MPM List or not. When mpm_flag is equal to 1, the            intra mode of current block is in the MPM list, when            mpm_flag is equal to 0, the intra mode of current block is            not in the MPM list.        -   Parse a mpm_idx which have value between 0 to N−1 (includes            0 and N−1). If N is 1, the mpm_idx is not parsed but as            inferred as 0.        -   obtain the intra mode of current block with default_list            [mpm_idx].        -   Predicting the block based on the obtained intra mode.

In an example, there is no block based binarization and MPM listconstruction in the embodiment.

In one implementation, the default mode list has a length of 4, and thelist is comprised of following entries with the specified order, Planarmode, DC mode, vertical mode, and horizontal mode.

In one implementation, the default mode list has a length of 3, and thelist is comprised of following entries with the specified order, Planarmode, DC mode, vertical mode.

In one implementation, the default mode list has a length of 3, and thelist is comprised of following entries with the specified order, Planarmode, horizontal mode (e.g., 18), and vertical mode (e.g., 50).

In one implementation, the default mode list has a length of 3, and thelist is comprised of following entries with the specified order, Planarmode, vertical mode, and horizontal mode.

In one implementation, the default mode list has a length of 2, and thelist is comprised of following entries with the specified order, Planarmode, DC mode.

In one implementation, the default mode list has a length of 1, and thelist is comprised of Planar mode only.

In one implementation, the binarization of mpm list index uses truncatedunary code, the maximum value of the truncated unary code is 3, when afirst MPM list has 4 intra modes, and the mpm_flag is always set to true(the value of the mpm_flag is 1).

In one implementation, the mpm_flag is always set to true (the value ofthe mpm_flag is 1). The binarization of mpm list index uses truncatedunary code, and all the bins are CABAC by-pass coded. The default MPMlist has a size of 3, and maximum value of the truncated unary code is2, when a first MPM list has 3 intra modes with the following order:Planar mode, horizontal (e.g., 18) mode, and vertical (e.g., 50) mode.

In one implementation, the mpm_flag is always set to true (the value ofthe mpm_flag is 1). The binarization of mpm list index uses truncatedunary code, and all the bins are CABAC by-pass coded. The default MPMlist has a size of 3, and maximum value of the truncated unary code is2, when a first MPM list has 3 intra modes with the following order:Planar mode, vertical (e.g., 50) mode, and horizontal (e.g., 18) mode.

The second MPM list could be constructed according to the methods in theITU-T H.265 and in the VVC, see the above examples and disclosures aboutthe MPM list construction process in ITU-T H.265 and in VVC.

Embodiment 5

As shown in FIG. 8 , a method of decoding a block of a picture,comprising:

-   -   Operation 801: obtaining an indication parameter for a current        coding block, wherein the indication parameter represents        whether a multi-hypothesis prediction is applied to the current        coding block;    -   Operation 802: when the indication parameter represents that the        multi-hypothesis prediction is applied to the current coding        block;    -   Operation 803: decoding the current coding block according to a        planar mode.

In one implementation, the multi-hypothesis prediction is combined interand intra prediction (CIIP).

In one implementation, the indication parameter is CIIP flag.

In one implementation, merge data is used to carry the indicationparameter. It means that the indication parameter is derived from themerge data syntax.

In one implementation, after applying the multi-hypothesis prediction tothe current coding block based on a value of the indication parameter,the method further comprises obtaining an intra prediction mode for thecurrent coding block according to a most probable mode (MPM) list and aMPM list index. In one embodiment, obtaining an intra prediction modefor the current coding block according to a MPM list and a MPM listindex through the following operations: indexing each of the intraprediction mode in the MPM list with a corresponding value of MPM listindex; parsing the MPM list index from a bitstream, which has valuebetween 0 to N−1; obtaining the intra prediction mode of current blockfrom the MPM list according to the value of the MPM list index.

In one implementation, the MPM list comprises at least planar mode.

In another implementation, the MPM list comprises planar mode and atleast one of DC mode, vertical mode and horizontal mode.

In another implementation, the MPM list consist of planar mode.

In one implementation, the method further comprises selecting planarmode for the current coding block from the MPM list according to thevalue of the MPM list index.

In one implementation, the MPM list is constructed from a pre-defineddefault list (for example, a default mode list) of modes for intraprediction, which has a size greater than N.

In one implementation, the MPM list index is coded into decimal orbinary representation.

In one implementation, the binarization of MPM list index uses truncatedunary code.

In one implementation, the first 4 candidates in the default mode listare used to construct a MPM list that has four intra modes. The order ofthe 4 candidates in the default mode list are same as the order of thecandidates in the MPM list. As an example if the default mode listcomprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the MPM list comprises the following intra prediction modes        in order:        -   1. planar mode,        -   2. DC mode,        -   3. Vertical Mode,        -   4. Horizontal Mode.

In one implementation, the first 3 candidates in the default mode listare used to construct a MPM list that has 3 intra modes.

In one implementation, the binarization of mpm list index uses truncatedunary code, the maximum value of the truncated unary code is 2, when aMPM list has 3 intra modes, and the mpm_flag is always set to true (thevalue of the mpm_flag is 1).

In another implementation, the first 3 candidates in the default modelist are used to construct a MPM list that has 3 intra modes. The orderof the 3 candidates in the default mode list are same as the order ofthe candidates in the MPM list. As an example, if the default mode listcomprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the MPM list comprises the following intra prediction modes        in order:        -   1. planar mode,        -   2. DC mode,        -   3. Vertical Mode

In one implementation, the first 2 candidates in the default mode listare used to construct a MPM list that has 2 intra modes.

In one implementation, the binarization of mpm list index uses truncatedunary code with a maximum value of 1, when a MPM list has 2 intra modes,and the mpm_flag is always set to true (the value of the mpm_flag is 1).

In another implementation, the first 2 candidates in the default modelist are used to construct a MPM list that has 2 intra modes. The orderof the 2 candidates in the default mode list are same as the order ofthe candidates in the MPM list. As an example, if the default mode listcomprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,    -   then the MPM list comprises the following intra prediction modes        in order:        -   1. planar mode,        -   2. DC mode,

In one implementation, the first one candidate in the default mode listis used to construct a MPM list that has one intra mode. In one example,the mode that is inserted in the MPM list is Planar mode.

In another implementation, the first candidate in the default mode listis used to construct a MPM list that has one intra mode. As an example,if the default mode list comprises the following intra prediction modes:

-   -   1. planar mode,    -   2. DC mode,    -   3. Vertical Mode,    -   4. Horizontal Mode,    -   5. V−4 mode,    -   6. V+4 mode,        then the MPM list comprises the following intra prediction mode:    -   1. planar mode.

The above embodiments are also applicable to a method of encoding ablock of a picture.

In one implementation, the binarization of mpm list index uses truncatedunary code, maximum value of the truncated unary code is N−1 when afirst MPM list has N intra modes, and the mpm_flag is always set totrue. If N equals to 1, mpm_idx is not signaled.

Although embodiments of the disclosure have been primarily describedbased on video coding, it should be noted that embodiments of the codingsystem 10, encoder 20 and decoder 30 (and correspondingly the system 10)and the other embodiments described herein may also be configured forstill picture processing or coding, e.g., the processing or coding of anindividual picture independent of any preceding or consecutive pictureas in video coding. In general only inter-prediction units 244 (encoder)and 344 (decoder) may not be available in case the picture processingcoding is limited to a single picture 17. All other functionalities(also referred to as tools or technologies) of the video encoder 20 andvideo decoder 30 may equally be used for still picture processing, e.g.,residual calculation 204/304, transform 206, quantization 208, inversequantization 210/310, (inverse) transform 212/312, partitioning 262/362,intra-prediction 254/354, and/or loop filtering 220, 320, and entropycoding 270 and entropy decoding 304.

Embodiments, e.g., of the encoder 20 and the decoder 30, and functionsdescribed herein, e.g., with reference to the encoder 20 and the decoder30, may be implemented in hardware, software, firmware, or anycombination thereof. If implemented in software, the functions may bestored on a computer-readable medium or transmitted over communicationmedia as one or more instructions or code and executed by ahardware-based processing unit. Computer-readable media may includecomputer-readable storage media, which corresponds to a tangible mediumsuch as data storage media, or communication media including any mediumthat facilitates transfer of a computer program from one place toanother, e.g., according to a communication protocol. In this manner,computer-readable media generally may correspond to (1) tangiblecomputer-readable storage media which is non-transitory or (2) acommunication medium such as a signal or carrier wave. Data storagemedia may be any available media that can be accessed by one or morecomputers or one or more processors to retrieve instructions, codeand/or data structures for implementation of the techniques described inthis disclosure. A computer program product may include acomputer-readable medium.

By way of example, and not limiting, such computer-readable storagemedia can comprise RAM, ROM, EEPROM, CD-ROM or other optical diskstorage, magnetic disk storage, or other magnetic storage devices, flashmemory, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer. Also, any connection is properly termed acomputer-readable medium. For example, if instructions are transmittedfrom a website, server, or other remote source using a coaxial cable,fiber optic cable, twisted pair, digital subscriber line (DSL), orwireless technologies such as infrared, radio, and microwave, then thecoaxial cable, fiber optic cable, twisted pair, DSL, or wirelesstechnologies such as infrared, radio, and microwave are included in thedefinition of medium. It should be understood, however, thatcomputer-readable storage media and data storage media do not includeconnections, carrier waves, signals, or other transitory media, but areinstead directed to non-transitory, tangible storage media. Disk anddisc, as used herein, includes compact disc (CD), laser disc, opticaldisc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wheredisks usually reproduce data magnetically, while discs reproduce dataoptically with lasers. Combinations of the above should also be includedwithin the scope of computer-readable media.

Instructions may be executed by one or more processors, such as one ormore digital signal processors (DSPs), general purpose microprocessors,application specific integrated circuits (ASICs), field programmablelogic arrays (FPGAs), or other equivalent integrated or discrete logiccircuitry. Accordingly, the term “processor,” as used herein may referto any of the foregoing structure or any other structure suitable forimplementation of the techniques described herein. In addition, in someaspects, the functionality described herein may be provided withindedicated hardware and/or software modules configured for encoding anddecoding, or incorporated in a combined codec. Also, the techniquescould be fully implemented in one or more circuits or logic elements.

The techniques of this disclosure may be implemented in a wide varietyof devices or apparatuses, including a wireless handset, an integratedcircuit (IC) or a set of ICs (e.g., a chip set). Various components,modules, or units are described in this disclosure to emphasizefunctional aspects of devices configured to perform the disclosedtechniques, but do not necessarily require realization by differenthardware units. Rather, as described above, various units may becombined in a codec hardware unit or provided by a collection ofinter-operative hardware units, including one or more processors asdescribed above, in conjunction with suitable software and/or firmware.

Following is an explanation of the applications of the coding method aswell as the decoding method as shown in the above-mentioned embodiments,and a system using them.

FIG. 9 is a block diagram showing a content supply system 3100 forrealizing content distribution service. This content supply system 3100includes capture device 3102, terminal device 3106, and includes display3126 in an embodiment. The capture device 3102 communicates with theterminal device 3106 over communication link 3104. The communicationlink may include the communication channel 13 described above. Thecommunication link 3104 includes but not limited to WIFI, Ethernet,Cable, wireless (3G/4G/5G), USB, or any kind of combination thereof, orthe like.

The capture device 3102 generates data, and may code the data by thecoding method as shown in the above embodiments. Alternatively, thecapture device 3102 may distribute the data to a streaming server (notshown in the Figures), and the server codes the data and transmits thecoded data to the terminal device 3106. The capture device 3102 includesbut not limited to camera, smart phone or Pad, computer or laptop, videoconference system, PDA, vehicle mounted device, or a combination of anyof them, or the like. For example, the capture device 3102 may includethe source device 12 as described above. When the data includes video,the video encoder 20 included in the capture device 3102 may actuallyperform video coding processing. When the data includes audio (e.g.,voice), an audio encoder included in the capture device 3102 mayactually perform audio coding processing. For some practical scenarios,the capture device 3102 distributes the coded video and audio data bymultiplexing them together. For other practical scenarios, for examplein the video conference system, the encoded audio data and the encodedvideo data are not multiplexed. Capture device 3102 distributes theencoded audio data and the encoded video data to the terminal device3106 separately.

In the content supply system 3100, the terminal device 310 receives andreproduces the coded data. The terminal device 3106 could be a devicewith data receiving and recovering capability, such as smart phone orPad 3108, computer or laptop 3110, network video recorder (NVR)/digitalvideo recorder (DVR) 3112, TV 3114, set top box (STB) 3116, videoconference system 3118, video surveillance system 3120, personal digitalassistant (PDA) 3122, vehicle mounted device 3124, or a combination ofany of them, or the like capable of decoding the above-mentioned codeddata. For example, the terminal device 3106 may include the destinationdevice 14 as described above. When the coded data includes video, thevideo decoder 30 included in the terminal device is prioritized toperform video decoding. When the coded data includes audio, an audiodecoder included in the terminal device is prioritized to perform audiodecoding processing.

For a terminal device with its display, for example, smart phone or Pad3108, computer or laptop 3110, network video recorder (NVR)/digitalvideo recorder (DVR) 3112, TV 3114, personal digital assistant (PDA)3122, or vehicle mounted device 3124, the terminal device can feed thedecoded data to its display. For a terminal device equipped with nodisplay, for example, STB 3116, video conference system 3118, or videosurveillance system 3120, an external display 3126 is contacted thereinto receive and show the decoded data.

When each device in this system performs coding or decoding, the picturecoding device or the picture decoding device, as shown in theabove-mentioned embodiments, can be used.

FIG. 10 is a diagram showing a structure of an example of the terminaldevice 3106. After the terminal device 3106 receives stream from thecapture device 3102, the protocol proceeding unit 3202 analyzes thetransmission protocol of the stream. The protocol includes but notlimited to Real Time Streaming Protocol (RTSP), Hyper Text TransferProtocol (HTTP), HTTP Live streaming protocol (HLS), MPEG-DASH,Real-time Transport protocol (RTP), Real Time Messaging Protocol (RTMP),or any kind of combination thereof, or the like.

After the protocol proceeding unit 3202 processes the stream, streamfile is generated. The file is outputted to a demultiplexing unit 3204.The demultiplexing unit 3204 can separate the multiplexed data into thecoded audio data and the coded video data. As described above, for somepractical scenarios, for example in the video conference system, theencoded audio data and the encoded video data are not multiplexed. Inthis situation, the encoded data is transmitted to video decoder 3206and audio decoder 3208 without through the demultiplexing unit 3204.

Via the demultiplexing processing, video elementary stream (ES), audioES, and subtitles are generated in an embodiment. The video decoder3206, which includes the video decoder 30 as explained in the abovementioned embodiments, decodes the video ES by the decoding method asshown in the above-mentioned embodiments to generate video frame, andfeeds this data to the synchronous unit 3212. The audio decoder 3208,decodes the audio ES to generate audio frame, and feeds this data to thesynchronous unit 3212. Alternatively, the video frame may store in abuffer (not shown in FIG. 10 ) before feeding it to the synchronous unit3212. Similarly, the audio frame may store in a buffer (not shown inFIG. before feeding it to the synchronous unit 3212.

The synchronous unit 3212 synchronizes the video frame and the audioframe, and supplies the video/audio to a video/audio display 3214, viagraphics processing unit (GPU) in an embodiment. For example, thesynchronous unit 3212 synchronizes the presentation of the video andaudio information, while ensuring that data buffers in the decoders donot overflow or underflow. Information may code in the syntax using timestamps concerning the presentation of coded audio and visual data andtime stamps concerning the delivery of the data stream itself. Timestamps are generally in units of 90 kHz, but the System Clock Reference(SCR), the Program Clock Reference (PCR) and the optional ElementaryStream Clock Reference (ESCR) have extensions with a resolution of 27MHz.

If subtitle is included in the stream, the subtitle decoder 3210 decodesthe subtitle, and synchronizes it with the video frame and the audioframe, and supplies the video/audio/subtitle to a video/audio/subtitledisplay 3216, via GPU in an embodiment.

The present disclosure is not limited to the above-mentioned system, andeither the picture coding device or the picture decoding device in theabove-mentioned embodiments can be incorporated into other system, forexample, a car system.

The invention claimed is:
 1. A method of coding a block of a picture,comprising: obtaining an indication parameter for a current codingblock, wherein the indication parameter indicates whether amulti-hypothesis prediction is applied to the current coding block; whenthe indication parameter indicates that the multi-hypothesis predictionis applied to the current coding block, coding the current coding blockaccording to a planar mode, wherein the multi-hypothesis prediction is acombined inter and intra prediction (CIIP), and the indication parametercomprises a CIIP flag.
 2. The method of claim 1, wherein the indicationparameter is determined based on a merge data syntax.
 3. The method ofclaim 1, further comprises: obtaining the planar mode for the currentcoding block according to a most probable mode (MPM) list.
 4. The methodof claim 3, wherein each of intra prediction modes in the MPM list isassociated with a corresponding value of an MPM list index.
 5. Themethod of claim 4, wherein the method further comprises: parsing abitstream to obtain the MPM list index, wherein the MPM list index has avalue between 0 to N−1, and wherein N is a number of entries of theintra prediction modes in the MPM list.
 6. The method of claim 5,wherein the method further comprises: obtaining the intra predictionmode for the current coding block from the MPM list based on the valueof the MPM list index.
 7. The method of claim 4, wherein the MPM listcomprises at least the planar mode.
 8. The method of claim 4, whereinthe MPM list comprises the planar mode and at least one of a DC mode, avertical mode and a horizontal mode.
 9. The method of claim 4, whereinthe MPM list comprises only the planar mode.
 10. The method of claim 4,wherein the MPM list is based on a pre-defined default list.
 11. Themethod of claim 6, wherein the MPM list index is coded into a decimalrepresentation or a binary representation.
 12. A coder, comprising: amemory storage storing instructions; and one or more processors incommunication with the memory storage, and upon execution of theinstructions, configured to: obtain an indication parameter for acurrent coding block, wherein the indication parameter indicates whethera multi-hypothesis prediction is applied to the current coding block;when the indication parameter indicates that the multi-hypothesisprediction is applied to the current coding block, coding the currentcoding block according to a planar mode, wherein the multi-hypothesisprediction is a combined inter and intra prediction (CIIP), and theindication parameter comprises a CIIP flag.
 13. The coder of claim 12,wherein the indication parameter is determined based on a merge datasyntax.
 14. The coder of claim 12, wherein the one or more processorsare further configured to: obtain the planar mode for the current codingblock according to a most probable mode (MPM) list, wherein each ofintra prediction modes in the MPM list is associated with acorresponding value of an MPM list index.
 15. The coder of claim 14,wherein the one or more processors are further configured to: parse abitstream to obtain the MPM list index, wherein the MPM list index hasvalue between 0 to N−1, and wherein N is a number of entries of theintra prediction modes in the MPM list, and obtain the intra predictionmode for the current coding block from the MPM list based on the valueof the MPM list index, wherein the MPM list comprises at least theplanar mode.
 16. A non-transitory computer-readable storage mediumstoring program instructions for coding a sequence of frames of a videointo a bit string, wherein the program instructions, when executed by aprocessor of a coder, cause the coder to perform operations comprising:obtaining an indication parameter for a current coding block, whereinthe indication parameter indicates whether a multi-hypothesis predictionis applied to the current coding block; when the indication parameterindicates that the multi-hypothesis prediction is applied to the currentcoding block, coding the current coding block according to a planarmode, wherein the multi-hypothesis prediction is a combined inter andintra prediction (CIIP), and the indication parameter comprises a CIIPflag.
 17. The method of claim 5, wherein the MPM list includes a firstMPM list and intra prediction is based on one of the entries in thefirst MPM list when the multi-hypothesis prediction is applied to thecurrent coding block, wherein the MPM list includes a second MPM listand intra prediction is based on one of the entries in the second MPMlist when the multi-hypothesis prediction is not applied to the currentcoding block.
 18. The method of claim 1, further comprising: obtainingthe planar mode for the current coding block according to a mostprobable mode (MPM) list, wherein each of one or more intra predictionmodes in the MPM list is associated with a corresponding value of an MPMlist index.
 19. The coder of claim 12, wherein the one or moreprocessors are further configured to: obtain the planar mode for thecurrent coding block according to a most probable mode (MPM) list,wherein each of one or more intra prediction modes in the MPM list isassociated with a corresponding value of an MPM list index.